When it comes to gambling (at least in the casino context), I struggle with the idea of a believer allowing himself to be present in such an environment-which seems to me would be full of evil and temptation. It makes me tremble to think that we have become so at home with worldliness that we wouldn't feel as aliens in such a place. In addition, gambling can become an addiction and great losses can be experienced.
As far as proceeds of gambling going to help the church, I have thought of this as well. I have heard many from my parish mentioning that when such money is used to help the church, a less than desired result occurs-it's as if God's blessing is not there.
As far as church attire is concerned, I think it is very easy to dress modestly, humbly, simply, yet with grace and neatness. We can dress attractively without spending a fortune on our clothing, and give the rest of the money to help the poor. A favourite book of mine "A Celebration of Discipline" by Richard Foster (a Quaker), mentions living and dressing in simple, unassuming fashion. I think he has a real point. Is it right to dress in a way that will intimidate or offend a brother or sister in the Faith, or should our adorning be inward, of the heart? I think I'd be more drawn to a simply and modestly dressed person in whom Christ is seen than the person who is all dolled up and dressed in a flashy manner.