[alkonaut]

> I question how useful a tool like this is for a skilled writer.

For a skilled writer who takes time to write "proper" prose, probably not very useful.

But for me, as a non-native english speaker who writes a lot of short english texts (emails, documentation, HN comments and so on), it could probably help.

For example, since I write both US and British English every day, a consistency warning is certainly helpful. I would also like a linter to help the flow of text, for example by pointing out when you aren't mixing up your sentence lengths in a good way. Oh, in that last sentence I accidentally missed that I used first person in the sentence before that! A linter as a chrome plugin would have pointed that out.