Iād be concerned about the security risk caused by their browser plugin, especially given their track record. Grammarly is usually a complete no-go once you have an infosec team.
> I don't know how I'd feel if my employer told me to use Grammarly.
I mean, everyone makes mistakes, or words things in ways that can get a bit long winded etc. I don't think it's that much different from having spell checking on in your word processor or browser. Seems like a nice tool.