I don't have an issue with it. Considering characters have no residence the mail system allows for me to pick up the item when I'm ready for it and or it is stored within the system for 30 days. That's a Win / Win in my book.
With hirelings maxed, the mailbox gets filled in 24 hours. If I'm too lazy and don't open/delete everything quickly enough, nobody can message me ingame.
Not so much of a win/win imo