One feature of an email client (Outlook, Thunderbird, etc.) is the ability to manage several mailboxes simultaneously. It's nice to see all your Inboxes on one screen.
SmarterMail webmail has a feature called Message Retrieval which can open IMAP mailboxes on other systems. That's nice, but it appears to be download only. It's not a 2-way connection.
Suggest making it 2-way so when you delete/move/read a message in SM, it updates the remote IMAP server. In other words, process mail on the remote server just like you process mail locally.
This would eliminate one of the reasons to use an email client! Thanks,
Kevin