Actually toasters need to be able to switch off a huge current, which causes arcing. This arcing may slowly burn the PCB and desolder the metal contact mounted on the PCB. At least that's what happened with my last toaster after >5 years. Repaired it once, then after a year it broke again, but this time the PCB through hole was severely burned and it wasn't trivially fixable anymore.
Motorized mechanisms... hmm. Well, sometimes toasters pop up toasts too hard making them land on the floor.
This isn't really true. The heating elements are pretty much entirely a resistive load, which do not cause arcing when switched off. What desoldered your PCB might be the heat itself.
There was visible arcing every time the toaster popped up the toasts though. Now that you mention it, I'm kinda curious what exactly was causing it. (Too late of course.) It's not the first toaster I've seen that produced a flash of light every time it was done though.
Motorized mechanisms... hmm. Well, sometimes toasters pop up toasts too hard making them land on the floor.