Well it's not like altcoins would be accepted anywhere else than at exchanges.
All you can do with them is trade them.
But at the point where you want to put them for good use and buy something, you have to convert them either into fiat, or bitcoin.
And that's the point why I think the alt ralley helps bitcoin too.
A good part of the alts will end up to be bitcoin sooner or later.
Some altcoins seems has potential I guess, as right now we have a coin which has reach $200.
We know that people will always sell their alts for bitcoin or fiat money, but is that true? Not everyone agreed.
Well, bitcoin isn't perfect in crypto world, so altcoins were here to fullfil what people want, even though mostly case we see it as trading object to earn more bitcoin.