I am not sure why one would assume it is niche (someone said OCaml is "super-niche") just because Jane Street is a prominent user of it. In any case, yeah, it is an excellent general purpose programming language. I replaced a scripting language with it. I now use Go and OCaml instead of say, Lua, because I had to reimplement the wheel when I used Lua. Perl and other scripting languages were too slow for my typical use-cases.