Started as IT Manager at current employer 10 years ago and was the first time I'd ever encountered this.
Chairman (owner) always arrived early to open the post and then pass it on to other directors. They nosed around and then distributed what they thought "suitable". Claimed it gave them a chance to "keep abreast of the situation". I think they just wanted to read The DP Managers Diary each week.
Chairman retired, passed company on to two kids who really think they have more important things to do. Post is still opened and orders, cheques, remittances etc are passed on asap.