This is purely anecdotal but as a Gemini user I'd use their stable coin if it was accepted on any of the other exchanges I use. I'd actually prefer to use it to buy altcoins than to use a BTC/ALT pair.
Same here. If Gemini offered DAI I'd be more likely to purchase it but GUSD only has a small amount of 3rd party services using it. The only one I can think of is BlockFi right now.
Likewise. But the demand side isn't us, it's exchanges.