I'm guessing that in this context, "useful" is intended to mean "useful in conveying information" rather than "useful in accomplishing some goal." It sounds a

I'm guessing that in this context, "useful" is intended to mean "useful in conveying information" rather than "useful in accomplishing some goal." It sounds a bit like saying "you're only human" -- which is of course unlikely to convey any new information, but could still be useful for its emotional result.