The way I see it, I think it might just play out like this:
Lightning as an L3 for LSP infra and some self-hosters.
Fedimint ecash for custody services.
Cashu ecash for self-hosters and potentially with their own smaller communities.

Inherently, while one might ask why use ecash versus standard sats, truth is, ecash has some advantages:
- More private
- Actually zero fees
- Offline (PoC) usage

As a self-custody maximalist, I too wondered about what ecash could bring to the table but the reality is, given the benefits, if you self-custody in standard LN already, you might as well run a mint too.

If you dont't self-custody, you still have the above benefits and with federated mints there are less chances for rugpulls. I believe cashu also have plans on addressing the potential for rugpulls from angles that standard LN is unable to offer due to inherent limitations.