[geokon]

I've never seen this implemented in a way that isnt confusing. It goes to some "Outbox" and you no longer understand why it stuck there and how often it's retrying. You can also have weird failure modes where the mail is sent but not saved to the Sent folder. This is also not obvious to display in a background process

But.. it seems like a solveable problem..

[ashwagary]

I prefer email sitting in the outbox for a short period of time before send/receive completes, it has saved me from mistakes enough times that it is worth the delay.

[lawgimenez]

This is what the Mail app in macOS does. Disappear in background, outbox for the moment and let me compose another email.