Will the new pets that assist us in combat be something that we see literally every player with just because there are no benefits for not having one?
I am not concerned with wether or not they are needed to kill stuff, since this game is definitely completable without them.
What I am wondering is if this will become the only playstyle - if there are no benefits for playing otherwise.
You won't be able to avoid getting them. As I've understood it, they will be equipped similarly to any other gear. Likewise, you can go without everything but armour and headgear. So I'm guessing it is optional but there'll be no gain in not bringing a sprite down in the Clockworks.