Some of the trophy chasing is a carry over from earlier days of mobile. Competition, and recruitment, and with a side of tracking player activity.
Before the player base expanded so dramatically, being a high ranking guild really helped pull other super grinders to your guild. Super Grinders grouping up, meant much more gold generation for the guild, which led to vastly greater earning of resources.
It’s a bit hard for me to explain how many more resources Match Makers was earning back when the iron keys and gem->gold loop existed.
So I know we still use Trophies in Vn4ever to help track activity and commitment. We’ve stopped trying to challenge for the very top ranks. Sure, we’d like to stay top 5, but we allow vacations, and have a lot of players that can’t push more than 400 trophies a week.