But I'd say the biggest draw for me now is that Janet has a lot made a lot of choices I agree with.
It's language that boots up very quickly, makes for easy building of CLI tools, compiles to statically linked executables, has full compile-time metaprogramming (Lisp style), and can interface with C libraries very easily.
It doesn't solve any particular novel problem better outside of PEGs, but it makes a lot of the right decisions. And, being a Lisp-like, it also gives enough expressive power to help you build things your way, if you want.
Most of that probably appeals to folks who a) have been programming for a while b) don't hate parens c) Are ok forging in untread territory
Janet isn't something I'd build a business on, not quite yet, but it has been a very, very satisfying hobby, and I've written a lot of small tools in it, more than Nim or Go during my times with either of those.