I appreciate this has been debated extensively already - but while crypto currency (especially stable coins) can be a worthwhile alternative to fiat money, bitcoin really isn't. A significant crash or surge happens every couple of weeks.
So 2 key features of a crypto-currency are lacking in stablecoins: censorship-resistance and absence of centralized trusted parties.
That you can move them on a blockchain (as long as permitted) with your private key is not much different from signing TLS connection in your Venmo. But with higher fees and latencies.
I don't mean to be mean, but if you have a fundamental security issue, "solving" it with a complicated protocol that still has the same security issues deep at the core, sounds like "scam" to me. Venmo, PayPal and Bitcoin are fair in their offerings: you know who you trust with what and that's the security model without any sugarcoating.