Some people live on $200 a month, so they definitely can't afford to spend that amount on gambling. And by the way, if a player sees that he is not able to win, it would be better for him to buy bitcoin for this money, and bitcoin would bring a good profit even without bets.
Now you are comparing gambling with investment. Of course, investment is far better than gambling. But you have to be careful about where you are going to invest. If you invest in Bitcoin, that is a great asset. But if someone invests in altcoins too, they have to be picky. One should not invest in any altcoins. Most of the alts dump when Bitcoin moves sideways. When altcoins pump, they pump a lot. When they dump, they start to bleed. So, the altcoin investment is nothing better than gambling.
But as you said, Bitcoin investment is better than gambling. But the purpose of gambling and investments is totally different.