Comment by literalAardvark

But.. Internet mail is not a lossy system. Quite the opposite!

Unless providers do insane things (e.g. accept then discard), it is much safer than snail mail, where messages may not arrive and not cause the sender to be notified of non-delivery either. With email, the sender gets explicit per-recipient-and-message feedback on what the recipient provider has accepted responsibility (to not lose them) for.