Yes I agree. Also if you know your business won't need a lot of dev, like stuff like Instagram where I think they were still at 60 engineers even after hitting 1B active users, it can also be a good thing to use a niche (but viable) language to attract some bright engineers and they will be thrilled to be able to have a job to use it. Now I don't have such startup (yet) so I can't do it :)
I just wish ReScript would have gained traction and replaced Typescript. But who knows maybe it can still happen.