In a lot of keyboard designs, you'll solder an Arduino Micro Pro to the PCB. It has, I dunno, 18 pins or something. Without a professional desoldering station, it's almost impossible to remove. I tried with desoldering braid, wick and pump but still managed to damage the Arduino. A more experienced person tried with a heat gun, also damaged the Arduino.

They certainly can be if you're not very good at desoldering. Especially BGA parts which require laborious re-balling for reuse.