Some apps (like banking) may not work on rooted phones.

They use Google SafetyNet to check for root. There are ways to trick SafetyNet on a per-app basis

Even if you root your phone properly, you may not be able to unroot it.

With Magisk, it’s as easy as flashing a single file, and if you want to be thorough, you can just wipe a few partitions and re-install your ROM