That said, I do use LFE for a lot of personal projects. I don't mind it being niche-ish largely because Virding wrote it to be a very thin wrapper around vanilla Erlang, so as a result there's not a lot to mess up. With the exception of macros, there's really not many changes to the semantics from regular Erlang, meaning that the transformation to and from LFE is trivial. LFE mostly exists to keep the syntax consistent and cleaner, and while the language is kind of toy-ish, it almost doesn't matter.
Honestly, I'd be a lot more worried for something like Joxa or Clojerl, not because they aren't awesome projects (they are), but they don't have as direct of mappings to the BEAM semantics.
Also, Virding is very active on the #lfe Erlangers Slack, so typically when I have a question, it is resolved pretty quickly.