From an entirely armchair commentator, I think so - the exchange of ideas and enthusiasm among Emacs-likes can only benefit both projects and Lisp-based editors in general. (The reason I’m very armchair is because use LyX when I want to write technical documents, which does leave out one of TeXmacs’s really important use cases.)

This year we got to have a cluster of talks that were about not-entirely-Emacs things, and last year we had one about Lem too (https://emacsconf.org/2023/talks/emacsen/). We've figured out multiple tracks, so we can handle cross-pollinating with other communities while still keeping lots of stuff for people who want to focus on Emacs. Proposals welcome! =)