If you really wanted to use the others, why wouldnt you just convert your Bitcoin to monero at the time you need to use it?
Anything not in Bitcoin goes down when prices in Bitcoin.
Discussion
Swapping from Bitcoin to other currencies takes about an ~1+ hour, and fees, on top of the settlement time, and fees of the currency I'm swapping into.
Whereas having different currencies natively reduces this down to 15 to 20 minutes with native privacy maintained, and low(er) fees.
This could be true more so of other currencies like BCH, Litecoin, XRP, etc. but I haven't used them enough to say on those ends.