The 1000 to go, when called from the PF, has a couple of purposes: 1- someone is monitoring the flight path 2- include the whole crew to the loop by increasing situational awareness of the team (and this is how it is defined on our SOP), and to let the PM know about the progress of the flight since PM might be busy playing secretary for the company 3- make sure nobody has gone incapacitated at some stage.
I agree the ones calling just passing their 1000 to go on their altimeter is annoying, since probably my altimeter has not gone through yet but about to go. I usually wait past 300ft (definition of occupied FL/altitude), and then call 700ft to go.
By the way, it is amazing how much paperwork / tablet work the PM has to sort out for the company these days.