One advantage of stablecoins is price stability. Merchants don't have to worry about price volatility when transacting in stablecoins. In the past and present, there have been a handful of projects proposing issuing altcoins (non-stablecoins) that will lead the future of crypto payment. What's the fate of such projects, will there ever be considered viable?
Stable coins are going to swallow most of these Altcoins, some of them have no reasons to exit because they have no real usecase. We all saw Tether move pass Ripple into number three and I expect the growth to continue to increase.