Rate limits exist to keep one integration (or one bad actor) from overwhelming a shared system. They're usually expressed as something like "100 requests per minute" -- go over that, and the system starts rejecting or delaying calls until the window resets.
Rate limits matter enormously for any integration moving a large volume of data (a big migration, a high-traffic sync), where hitting the ceiling can silently stall a process that looked like it was working fine.
