Honestly speaking why would you play on unknown or new gambling site where you can play the same game on the existing gambling site without having a problem? One reason is that they offer something that the existing gambling site don't for instance a opening promotions like free bets and many more. Usually that's the only way they can get players and also not because the gambling site is new it cannot be trusted.
It's really rare for me to change the gambling site that I use to gamble on, like why should I change the platform as you said? unless there is something new on a different gambling site that catches my attention and makes me want to participate? Unless there's something that really interests me, I can't be bothered to switch. While what you said is correct, some gamblers like to take the risk and test out new gambling sites, even though it could be a bad or good decision since they're not familiar with it.