of course it is profitable to do that in the long time if you make it as a long term investment, if i had a lot of bitcoins i would definitely invest my money as it would make more easy money
no "of course," just should be. theres no telling if the casino might have quite a few lucky bettors in the long term, its just a lot more likely that investing will profit as opposed to betting as a player. however, the trust in the site that allows investments is a risk too, you are handing over control of your coins to the website, and they could just take them and disappear if they wanted to.