This may sound ignorant but it looks like ERSC intends to situate itself as a middle ground between tools that are supported by more general purpose protocols (i.e., Tangled and apparently, eventually, Forgejo) and tools that trying to maintain the whole shebang (like Radicle).
The exception here being that ERSC also apparently intends to be less dependent on git than the others too.
If true, they have the clear advantage.