On ICO investing you will have to wait for several months like 3 to 10 months before the ICO is finished and you'll wait to 2 to 3 months more to get the coin in the market and there's no guaranty that you will make a profit, majority of the coins coming from ICO are down 50 to 90% and that was over a year of waiting.
on online gambling, if you play your cards right like when you have control on when to stopped and you have built a strategy, you can win over and over again and you can withdraw your gains immediately
As compare to ICO, wherein you are giving false hope by the people behind the project and you get too excited about it. But when the time comes, damn, you get disappointed because the supposedly profit are nothing, not even close to their ICO price prior to listing.