"My daughter has a potato-mashing attachment for her food processor."

Oh, don't get me started on those bally attachment things :)
I think there's an attachment for every day of the year on most processor type gizmos!
I've only ever used the main blade (for everything except coleslaw) and the grater attachment (for coleslaw). The rest of them go in the bin nowadays - mainly because I don't have the space to store as much useless clutter as I used to.

No, it's a hand masher for me all the way. In fact I use an old inherited so-called "vintage" one, still going strong from the 60's (maybe even the 50's) despite the fact that the green and yellow paint has all flaked away now (which is probably not such a band thing considering the sort of stuff they used to put in paint back then).