Doing Ecommerce in bitcoin or lumens is tough because the value can change drastically.
With a popular enough stablecoin, won't merchants start preferring that over bitcoin?
Once bitcoin is no longer the preferred crypto for ecommerce, won't that erode confidence/the foundation for using it as a store of wealth? And thus it's ability to be digital gold will be undermined?
Bitcoin could be like Yahoo in 1999.
Libra could be Google.