I think one of the issues is that its a closed ecosystem with no easy way to interact with the rest of the fiat world. What's the point of having USD if you can't easily spend it where ever you go? This is a general problem with building stablecoins on Bitcoin in general.

You could go to Bitrefill and buy gift cards using stablecoins like this but that adds a layer of extra actions/complexity that users probably don't want to deal with. Its unlikely that a lot of vendors accept these stablecoins too. I would go as far as to say that there are more vendors willing to accept just straight sats rather than stablecoins backed by sats.

I'm not against the idea of stablecoins on Bitcoin, but adoption is hard.