Wait, the letter, do not hurry

A couple of months ago, I had an idea how to slightly improve any email service. The idea is so simple that I even feel embarrassed: after all, if it has not yet been implemented, then most likely I’m a fool and I don’t see any obvious reasons. But it could be otherwise, right?

All of us use e-mail, and many have repeatedly encountered an unpleasant situation when a thought like “the devil seems to be writing the wrong thing ...” came right after clicking the “Send” button. Moments of awkwardness are replaced by the desire to quickly come up with something to fix everything, and then the realization that nothing can be fixed. You can only adjust. The problem, despite the respectable age of email as such, is now only partially solved. In particular, as is well known, more recently, the GMail service introduced the "atu" undo function, which allows you to recall a departed letter, but no later than a few seconds after sending it. Not only, of course, but at least something. Moreover, other services, as far as I know, have not yet been equipped with such a thing, which is strange. It is clear that it is impossible to technically return the bytes sent: what went online, then left irretrievably. Given the data transfer rates from one server to another (in the worst case, seconds), it is almost impossible to intercept the bytes sent on the way to the destination. They can only be wiped upon arrival or ... not expel at all! And here is the time to go to the essence of the idea (as it turned out - not only mine :).

The idea is that a letter after clicking the "Send" button would have left the addressee not immediately, but with some delay. The sender receives a message like "Your letter has been sent", but in fact it is still hanging somewhere in the buffer and, looking at the clock, waits for the doors of the gateway to be opened and released. Well, or give the order to turn around to the starting position. There are so few delays in five seconds that you don’t have it at all, but a minute or two is more than enough.

Yes, a couple of minutes is a long time, but is it so critical when it comes to the electronic? Every second of the delay is annoying except when communicating via Skype, jabbers and other messengers, where we are having a dialogue, and by e-mailing we rarely expect to get an answer even after 5 minutes, so our message will not reach us immediately or a minute later. , but this minute can save us from embarrassment.
')
Obviously, you can implement this sending delay directly on the client or server side (I forgot that if you work on the client side, when you close the browser, everything will fly to hell), while either giving the user the opportunity to adjust the lag himself, or completely enable this feature by default without special mention of that, so as not to embarrass anyone.

And now, friends, the question is: am I a dummy?

UPD: Apparently, GMail implemented its undo in this way, but then two things are not clear: why only 5 seconds to cancel and why only garlic has it?
UPD2: Mail.ua service also has the function of a letter recall within five seconds. Why is five again? Why so little?