I suspect they don’t care. They have “an app”.

It’s probably developed by one or two people, likely not full time, who spend most of their time on it implementing whatever the next special promotion needs, not stuff users want.

Because that’s what they’re told to do with the little time allocated to it.

it's probably a random app development studio. the gym most likely doesn't employ their own app dev employees. the app developement studio basically cares about two things: earning money and keeping their client just happy enough so they come back. the users of the app are not their customers and at best a secondary concern.