Mail facade should use a mailable's custom mailer automatically

[florentpoujol]

When working with mailables, you can pass an instance to the Mail facade send() method and it will extract everything needed from the mailable instance, including the recipients, but not any custom mailer that may be set on the mailable.

I understand this is not a bug and is because the mail facade will work with the default mailer, unless we expressly call the mailer() method before we call send() like that :

Mail::mailer($mailable->mailer)->send($mailable);

But since the point of mailables is to encompass everything related to a single email, shouldn't it be the case automatically ?