They do, as long as you are careful. Mind you, not had an opportunity to use mine for years. I recall when I was a LOT younger, I'd not seen the tool, and wondered how the BT (or probably, PO back then) guys managed to knock them in - did they use a very small hammer ?
Correct, they generally don't look very pretty - not helped by the usual "who cares about aesthetics" approach to doing stuff.
Yes, had a few cases of this. In one case, we had a call from a client to say their internet had gone down. It just so happened that they'd just had their alarm installed - and along one run, the alarm installer had put one leg of nearly all the staples through the adjacent phone cable.
Another one was a network cable that worked it's way from the ground floor to the second floor in what had been an old house but which was now an office/training centre. Luckily by then I'd got my own TDR network cable tester (and had it with me) so could identify that there were multiple breaks due to staples - and more luckily, there were still two pairs intact so I was able to re-wire the run to only do 100mbps which was preferable to replacing the whole cable.
