It's much more complicated than that:
https://huobiglobal.zendesk.com/hc/en-us/articles/360000170601-Announcement-on-Launching-HUSD-solution-on-Huobi-GlobalThey will accept deposits of PAX, USDC, TUSD and GUSD, but these coins will all be credited to your account as "HUSD". They therefore combine all the stable coin markets in to one and offer HUSD/BTC, HUSD/ETH, etc. When you want to withdraw your HUSD, you can choose which of the 4 stablecoins you want to withdraw.
Sounds great in theory, until we get a repeat of what has happened with Tether and the four stablecoins are all worth different amounts. I'm also not sure what they would do if a large number of people all want to withdraw in the same stablecoin in a short period, and they don't have enough reserves. I guess they would have to suspend withdrawals while they sell some other assets to buy enough of the coin to fund every withdrawal.
All-in-all, seems like an overly complicated system and one I will be staying away from, at least for now.