Earlier quoted context omitted.
But why? Why shoehorn everything into a single technology? Is it so that certain people never have to learn anything else in their entire life anymore?
Well, a pretty good reason is that C# is statically typed, which a lot of developers prefer. It's arguably a much more powerful language than JavaScript too. Personally, I work with both C# and JavaScript, and I'd happily use the C# version of Playwright to write and run UI tests.
Don't know, everyday I see more and more C# devs preferring Typescript for new projects.