Incomplete distinction:

For institutions, stables are primarily a messaging protocol innovation, like ACH or SWIFT, but where the 'medium is the message' (the message is both the state change and the trusted, instant settlement -- this the key innovation of blockchains) vs. legacy systems where the message and settlement are independent processes.

For consumers, stables are primarily an innovation in convenience and economics/incentives. They combine the potential for rewards and better economics with the convenience of instant global financial access (still being built out)