If the modern production world came to an end.. and that was the only alternative to shooting and especially hunting for food.. I would attempt making the black powder and using it. I mean what choice would I have.
But first off insurance companies find out your making black powder they get real excited. Consider, even under professional circumstances, these factories blow up, so what chance would I have... probably slim to none.
As for would I shoot it.. the problem I can see in shooting it would be the consistency of the powder. Even if the powder "home made" was under powered.. you could compensate for that. But what might be under powered in this batch might be very different in the next. You would do a lot of sighting in and checking loads I believe (which I do now with factory powder).
Personally as much as a DYI that I am.. I would not mess with the black powder.