(This is an analogy, but it's almost literally the reality for a massive global market that not seen by the mainstream)
I'm not sure where you would read about it. It's like this... Bahamas dollars are pegged 1:1. They can be spent interchangeably in the Bahamas. You can redeem them 1:1 in the Bahamas. Very credible.
But most people are not in the Bahamas, and can't redeem them where they are. The Bahamas won't let just anyone in, and it's expensive to go there anyway. (Oh sure, if you're American and live in Florida it's no big deal, but if you're Chinese or Indian or something it's a big pain in the ass) There are money changers in other places that will take Bahamas Dollars, but they'll only take your B$100 notes and you're looking at like 4% loss to sell them, and for all your 20s, 10s, etc nobody will give you more than 50% for them if they will accept them at all. So these things are somewhat redeemable if you're in Canada or France... but in many places they are not redeemable at all.
Or you could use this other thing called Tether that just works. It costs 0.25-0.50% to turn into local currency if you're talking $10,000+ amounts. It can be done in almost place on Earth where you have running water and electricity.
GUSD is basically like B$. So given that reality, it's a no brainer to take Tether over GUSD, even if you think Tether is shady.
This is also something I didn't get about Tether for a long time... it's actually successful because its operators are shady, not in spite of it. They have been doing whatever it takes to maintain actual liquidity, and has done so for years. Gemini does not, it just sits there and brags about how it could totally pay everyone back if it wanted to.