I completely agree with you that nowadays it's a lot safer and potentially more profitable to invest in a coin than gamble. The main reason is that the coin's success can be predicted based on it's main features, whereas in games you mostly deal with randomness. Moreover, when the casino owners are interested in you losing the money, coin owners are in a way interested in you winning, because if a lot of people earn something from buying a coin, it will attract even more people and thus the coin creators will become rich as well.
Nevertheless, surely, as mentioned by other members above, gambling provides you a different kind of experience and trading cannot compensate that one fully, partly because everything proceeds really slow in trading in comparison with gambling.