It's kind of niche but is getting bigger. The Discord server has 10k members, the biggest(?) Twitch programming streamer has been using it recently, JangaFX is big enough to be used by AAA game companies and a few large film studios, and I'm sure there's plenty of users who aren't on the Discord server.

If you're comparing it to Rust/C++ you must live in a cave or something. So yes. It's not that big. But it's probably in the top 10 of hyped languages of the current year. There's a bunch of languages from the 60's to 90's on Wikipedia that have probably never had as many users or software shipped as Odin.