A few uses have occurred to me, today.
if you had a petter sitter or house sitter, programming alexa with the answers to important questions like:
where's the towels?
when should Fluffy be fed
What do I do if there's a water leak? (happens more than you think in my house)
might be handy. It's a bit of a stretch, considering it's stuff you'd hope to write down. But if toss the sheet after the sitter leaves, you've got to do it all over again.
I suppose it might also end the "we've always kept those there!" argument over where the standard place to put the towels is and somebody "moves" them.
I think it'd be weird setting up all the anal retentive things your household normally knows and does, but once done, it might be useful.
Or...a friend who is a realtor was telling me about how they set up an Alexa in a house they're showing and feed it answers to questions about the property. There's apparently a skill for that kind of thing, but it is probably just basic stats from a realtor or tax accessor's site.
I suspect the flashcard thing would be better as a proper skill, because if you load all that data in, you probably just taught your brain the answers, and you'd get more re-use letting the world use it.