Next to Mastodon.world and Lemmy.world I am also running Calckey.world.
This was running Calckey, a Misskey fork. That was re-branded to FireFish (that's the danger of running sites with the software name in the URL... :-) ).
Unfortunately due to circumstances the FireFish software will no longer be maintained. Therefore I was looking for another Misskey fork that could replace it, and I found Sharkey.
This looks really nice.
So being who I am, I registered https://sharkey.world and installed it. It still needs some configuring and branding, but it works and you can use it! (As you will see it currently uses the Calckey.world branding)
I will write a brief how-to on migrating from Calckey to Sharkey and hope the calckey.world users will migrate.
The question doesn't make sense. They are projects with different purposes. and what kind of potential you are asking? popularity, ease of use, mass market, etc?