To me it's not about price. Liturgies can be compiled if one is able to follow along. My experience in the Malankara church really convinced me the screens are that much more useful, especially when I have that desire to participate in prayer at parts when I don't understand what is said.
Mina obviously wants to start a fight with the repeated attacks on the Malankara church...
Personally, I find myself on the side of not having projectors, but only books (if needed). But I think the variability of the liturgy, the organization of the book, and the role of the congregation all play a factor in whether projectors are useful.
Armenians pray in classical Armenian, and use no vernacular except maybe for the two or three readings (in my experience). The priest's prayers are, by and large, taken silently, and the variable portions of the liturgy are sung by the choir and/or deacons; I've seen very little congregational singing. But they have a nice book, at least in the US (contains the entire liturgy). It's not too thick, but the pages are pretty big, so it's annoying to hold after a while. But it's easy enough to use, esp. when the parish has some LED sign with the page number displayed in red. Once you are familiar enough with the order of the liturgy, you don't even need the sign, but unless you know classical Armenian or don't care about having even a rudimentary understanding of what's being prayed at any moment, the book is useful. I don't see how a projector would beneficial in this context.
Indians in the US pray in a mix of Malayalam and English; usually the majority of the service is in one language, but readings and some litanies may be done in the other. There is congregational singing, whether or not there's a choir, but for the most part, the responses (much more than just Kyrie eleison and Amen, btw) and hymns are the same every Sunday, so they can be committed to memory eventually, at least in one language. The variable portions are included in the book, which is fairly small and light (it only contains the deacons' and people's parts, as the priest's parts are part aloud and part silent, and there are so many anaphoras that could be chosen on any given day that it makes no sense to bother printing those). Thus, the book is not a terrible inconvenience to use in worship; when propers are sung, the page number will be announced by whomever is leading the singing. If there happen to be no proper texts for the day, generic texts will be sung, and those are usually committed to memory, so no announcement needs to be made, they'll just start singing. Personally, I don't think a projector would be beneficial here; newcomers and visitors can be helped along in following the liturgy by a) someone who helps them with the book, or b) just taking it in.
I suspect, though I have no experience to back it up, that the Syrians in the US have the same basic experience as the Indians, but with different languages being employed.
My experience with the Copts, however, is quite different. I don't know how Copts who grew up in the Church and know their rites well enough feel about projectors, but I certainly find it helpful. All the parishes I've visited use three languages almost interchangeably; it's not uncommon to have priests switch among the three languages in the middle of one long-ish prayer during the anaphora, for example. There are variable texts that seem longer than anything I'm used to just in terms of how long they are (without taking the chanting style into consideration). These, too, get divvy'd up into different languages. There are a number of readings, not all of which are in English. There's so much linguistic transition going on. And the rite itself is not visibly similar enough to other rites that you could just "tell" where you were in the service beyond "First we read and then we eat". Byzantine, Syriac, and Armenian liturgy (collectively, the bulk of Eastern Christianity) follow a very similar plan in the rite of the Eucharist; Coptic liturgy flows differently. I've used liturgy books in Coptic parishes in the past; they are bulky (they contain everyone's parts for everything for Vespers, Matins, and the Liturgy, including three anaphoras), and if you don't know how the liturgy works, you'll get lost fast. No one I've worshipped with ever seemed comfortable enough with the liturgy and the book to get me back on the right page. With a projector, everyone's "on the same page" with all the variation in text and language. It doesn't offend the eyes, and the computer programs created for this purpose are really good. The only time it really is a distraction is when someone doesn't know how to operate the projector or the computer program, or is not quick enough to flip to the next page. That's annoying and distracting. But assuming the person in charge of the computer knows what they're doing, I find it helpful to my participation. And it seems that there is congregational singing in Coptic parishes, so having texts displayed in all three languages helps you to keep up. If you don't need or want the projector, it's usually easy enough to tune it out.
I prefer books to projectors, and vernacular to classical languages, but we are in this world, not in our ideal world. And while we ought to work toward improving things, we may need to use crutches to walk from time to time. In most cases, my experience is that a book works just fine for this purpose. But strange as it may sound to some, I think projectors work better for the Copts.