I had one. My point is that was the finished thing. And it’s appeal to me was that it was free not that it was web based. Freeness required a VC. Was making web based email (if that era standard) a real hard technical challenge that only one dev team could do it?
I'd been building increasingly sophisticated CGI-based web apps at the time (as a hobby) and still remember being blown away with what appeared to be a fully functional email client running inside Netscape. This was before Javascript was commonly available or standardized, and certainly no XmlHttpRequest etc.