I have lost the link to an irreplaceable document where a bunch of designers and amateurs provide a list of fiction-first "what ... is good for" guidelines.
For instance : a Desert Eagle is good for blowing big holes. A butterfly knife is good for fumbling, cutting yourself and dropping it.
I think it's in a volume of Push, and maybe with Baker or Harper and Care Boss, but it really is fuzzy.
I thought it was in the "timetraveller sword" thread, but I can't find it anywhere...