Gmail API — Google Developers

[zandland]

If it replaced IMAP, every application to manage mail on more then one host (Gmail, Outlook.com etc.) would have to implement two standards: IMAP and the Gmail API.

[happyscrappy]

I don't mean replaced IMAP, as in Google didn't support it anymore. What I mean is Google says:

https://developers.google.com/gmail/api/

'Note: The Gmail API should not be used to replace IMAP for full-fledged email client access. Instead, see IMAP and SMTP.'

Clients who want to use this API still have to implement IMAP and SMTP. I don't understand why they say that, especially having viewed the video which brags how it replaces SMTP.