Because we always want something new, new design, new games, new features As it seems to us.... And we can not immediately know that this is a second-rate site, even if we heard somewhere that the site has a bad reputation anyway we are relying on their experience goes to check it 
It's already in the nature of humans to have a desire for new things even if the previous thing they have is still functional but fortunately there are people left who value their old stuff, same goes to playing gambling. Like for me, I think all gambling sites are the same. They only differ on names or on some themes but the gameplay was still the same so will I still bother playing on the others? I will only waste more money than usual.For those who want to try new casinos, it's important to check the feedback of others if you can't afford to test them in your own but you must still be vigilant after and always withdraw any balance left on your account once you finish playing, just to be safe.