"Great. Here is a stack of 100 letters. I give you 2 seconds to sort them by sender. Go!"
First of all, that's not what faces me when I get back from vacation. I have a stack of flyers, etc. which are nuked very quickly, a few bills, and then (if I'm very lucky) *one* actual letter. Secondly, why would I want to sort them by sender? I sort them by priority and that's really easy to do with physical mail.
"If you don't have separate work and personal email accounts ... Oh I see. I'm being trolled."
I have multiple accounts, but I do get some personal email on my work account. I also get email of varying importance at work, ranging from unimportant to urgent, and there's no obvious way to sort it without at least reading the subject and sometimes the body. Why should I have to sift through all kinds of stuff on my return? Once senders know I'm away, I can trust them to refrain from sending me unimportant stuff, and to send urgent stuff to the contact person in my initial auto-reply.