I do find the quote facility both useful and irritating.
Useful because it saves me trawling back when someone comments on another's post such as I agree with ABC when I haven't a clue what ABC said.
Useful because I can hit quote instead of copy, paste, brackets and all that.
Useful because a poster cannot be misquoted.
Irritating because the big blue boxes take up lots of space.
Irritating because when quoting a recent response to the previous quotes and responses, we get the whole sorry saga.
I think a quote facility is useful when used responsibly but can be over used 'quoteabuse' good word but can't remember who said it without trawling back.
Please, please, please don't anybody quote me.