Well gambling is one of the ways to have fun using cryptocurrency and it also offer the players to double or even triple their holdings if they win. It will portrait bad image to others especially those who have few knowledge about crypto and nothing we can do about that since most of the cryptocurrency have no real use case at the moment which is why people choose to bet their crypto instead of holding.
Gambling is an industry! Growing industry if I may add, especially online gambling industry. Money is going in and out, many people work in casinos or for casinos, even more people gamble everyday! Billion dollar industry! Can that be a problem to crypto? Absolutely not! Gambling is one the reasons of crypto expansion! Believe it or not, people had problems to find a place to gamble, in some countries its forbidden to gamble in real and online casinos, many countries (including my country where I live) didn`t have access to online casinos, country where are you from is not supported, simple message, with crypto we don`t have restrictions of that kind! And one more fact, its faster instant deposit and withdraws with crypto and lower fees, while with fiat you need banks, checking, that can last for days sometimes.