mutt can't speak SMTP ... wait, it can ...
... or why mutt should not but slowly becomes an "all-in-1" program.

mutt was developed with the concept of "one task per tool", enabling
performance through combination with other high quality modular
programs. This is an aspect of the "unix philosophy".

[...]

That's why --so far-- things have been kept separate (or out of mutt).

For quite some time basic MRA functionality has been included in
mutt, which some consider a breach of the concept and therefore demand
inclusion of SMTP support as well (and because "all the other MUAs have
SMTP aswell"). [...]

[...]

Well, it seems the force of the masses is hard to withstand though
... recently experimental minimal SMTP support has been added to mutt
as an option. [...]


-- http://wiki.mutt.org/?MailConcept