Fedimints are one potential scaling solution for Bitcoin, and I like that they are designed to be operated for existing groups who have existing affiliations/connections. For example, a community with a farmers' market, a group of local bitcoiners, a sports team etc etc.

The shared custodians as known members within their community therefore have social capital to protect, and presumably some sense of desire to see their community benefit from the Fedimint.

I like Carvalho's take on trust (WBD#758 with Zucco and Corrallo): Trust is a great way to scale - trust isn't inherently bad - the issue is who you trust (ironically (imo) John's not a fan of Fedimints).

IMO this is the crux of why Fedimints may blossom - at least in various bitcoin-related communities around the planet.

So downsides?

The provable 1:1 link between eCash and the underlying sats that the mint holds against which they've issued the eCash. Calle's and others been doing some work in this area - but just like exchanges, it's the issue not just of "show us how much bitcoin you've got in your reserves", but "show us that the amount of eCash you've issued is < reserves". Not a trivial problem.

There are no silver bullets.

By this I mean, there is no magic BIP (for covenants or whatever is being proposed) that will "fix" scaling. We will iterate and try multiple approaches - Lightning and Liquid are both good examples. We're a solid 5 years in to an operational Lightning network and there's clearly still many very rough edges.

Can Fedimints play a part - yep I believe they may be able to - keen to fuck around and find out %)