At the moment, I have Gmail on my watch. I can read, and respond to emails. It would be handy to have a Tbird watch app where I could do the same. I could add my IMAP and POP email accounts to Gmail, but I would rather not do that.
I was quite surprised that there’s no Wear OS app to accompany the Android release. I’m using a Samsung Watch 7, and after switching from Outlook to Thunderbird, I’m loving the Android app. However, not having Wear OS support is a bit of a drawback compared to Outlook.