Earlier quoted context omitted.
> Mimestream differs from other email clients because it uses the Gmail API rather than IMAP Technically speaking that make Mimestream not an email-client, but only a Gmail-client. It's only an email-client if it works with general email-providers, which this one clearly doesn't.
I think that's more than just a technical point. If someone sold me an email client that only supported one provider, I'd feel swindled. I would encourage them to reconsider their "email client" language. It's asking for a headache.
Their title on HN and website is "A native macOS email client for Gmail," and that's exactly what it is, especially if you were trying to be technical.
It's like bickering that it's not a native client, it's a macOS client, because it only runs on macOS. Or that you'd feel swindled if it didn't run on Gentoo because anything that calls itself "software" when it's really "Macware" is basically false advertising. It's an odd attempt at pedantry.