Actually Piggy was a “re-creation” of the other game, Granny, but they implemented better things and thats the reason for the success. Making copy cat games would be a really bad thing to do if all you did was steal the idea and not implement anything.
There are some “copycat” games that actually implements a thing to the original idea and creates it in a different way (Example: Spider, it has the same idea as Piggy but it implemented things and made the thing in a different way)
The bad thing about copycat games are that they end up making the original idea get a type of stereotype where people says its bad just because there are lots of versions.
Good thing to do would be innovating or simply improving and adding things to a idea and then putting it in your game.
Another great thing to do is that after you do that “innovated” idea, you should update the game (Which is probably the reason of most games out there being popular).