I also wonder how many paid users they have.

Seems like the starting price is USD $12/mo, which IIRC, costs more than my Office 365 Personal subscription.

In what sense? Ridiculously few or overwhelmingly many?

Honest question of someone using mostly local free software (as not in the cloud, as in free speech, not beer) and not living in an English-speaking country.

What do you mean? How can a number be ridiculous/overwhelming when you don't know it yet?

I believe most of their users are academicians - students writing their thesis. And I don't think a lot of them pay for its license themselves. It's their institute which purchases the license.