A place for them to communicate with their people without discord-honeypot gulag. You could do social badges of course - e.g. community creator, invited community creator, invited community member etc (see github examples). If someone already found their way to flotilla, and they stick around it means they are receiving value from your product. Find your super spreader customers, and just ask them/make it easy for them to spread the word.

A promise of Flotilla actually reaching feature parity where important with Discord is more than enough. Let early adopters feel involved by taking feature suggestions and make it easy to see progress being made towards the goal (could eg. be a Github issue called "Discordification with a list of features being checkmarked as they are completed, so people can go there to see the current status). Also, if you can push things faster forward by hiring or giving grants to devs in the community, letting the early adopters give you money that specifically will go towards discordification or specific features in that roadmap would be wise.