This isn’t built on top of Bitcoin, it’s built on Bitcoin hard fork. Also, why would you use stable coins and thus adding a centralised point of failure when Bitcoin already solves this? Just use it as payment rails.
- Because merchants do not want a volatile currency.
- Because people in countries with weaker currencies might be interested in accepting/transacting in something that gives them USD/EUR/GBP/JPY.
- Because there are DeFI protocols that are giving better returns than any savings account ever could.