I have $3000 USD to invest, is it worth it?
What sort of returns should I expect
Don't "expect" anything as it could turn out good or bad. Only gamble if you are ok with any possible outcome. If you can't afford to lose the $3000 then simply don't gamble. If you do decide, online Bitcoin casinos is a better option than a real casino. Try out Bitcoin dice sites where you can choose your win chance and try out different methods.