Yes, that's pretty much what it is.
Because those that are into trading of futures and shorting, they're mostly trading into an altcoin.
Actually, Bitcoin is much safer than trading with altcoins if you are going to analyze and trade with futures. It would be a good place to put a position if you are short in budget because you can leverage and make profit even in slight spikes.
Altcoin in futures, for me, is risky because of the high price movement compared to Bitcoin. Usually, what I see is that there are more retail traders who do futures with Bitcoin than altcoin because it is less manipulated than altcoin.
If you are one of those who trade with altcoins in futures, you are one of those risk takers, but if they are successful, the potential profit is massive.
That is what I see with most of the traders that are into futures, they're looking for some good entry with the altcoins as their pick and rarely I see one of them chooses to trade bitcoin in the futures.
But I agree with you, if someone is in need of a budget they can always look into BTC futures if they want to.
And just a gently reminder, this isn't for everyone and the newbies even hearing it makes them believe that they can make money out of it easily.