If you delete it, it will take out all your existing devices with it. Then you have to add them back with the system app. I do not think they ever got the migration working correctly. So if you have a bunch of stuff setup you are best off just updating to the latest user app version and going from there. I still am running the user app.
No, you do not need binding. However, to reverse this you may have to remove from the Kasa app and then reinstall. I DO NOT RECOMMEND removing.
Reminders:
Read the instructions (since it has been a while).
Some new Kasa devices may not install using this APP (both built-in and community). Kasa is transitioning NEW models and hardware versions to a different API. These devices install using the community Tapo integration. These are currently limited to Kasa Matter devices and the latest hardware version of the HS200 and HS220, and EP25.