Regarding the advantages, Gemini defined Dollar more protected. It is regulated by the US government, audits are constantly conducted, smart contracts are thoroughly checked.
It is also worth noting that the Winklevoss brothers have an excellent reputation, unlike Tether. The latter are constantly accused of manipulating the price of bitcoin, suspicious connections with the Bitfinex exchange and the lack of evidence of a Fiat reserve. Moreover, Winklevoss actively develop its cryptocurrency Empire, for example, actively trying to start a bitcoin ETF. With their reputation and drive, they can take their business to whole new heights in the next few years by pulling GUSD with them.