Speaking from experience, it functionally ruined them, at least the early macs -exact os/model unknown- we had (school computers well behind the curve and all). They’d need to be reformatted after. It would delete, then iirc just crash and you’d reboot into errors (my memory of this is spotty, it was a very long time ago)

I used to do that in the computer lab when I was supposed to be doing typing practice. Fucking hate typing “properly”.

Note: I am not a verifiable source, this is anecdata.