Sideslipper,
I'm with Kockayne, HD and ATCO Fred. It's often used as an 'attention-getter' for the controller, who may be working over half-a-dozen other a/c. Also, landlines/intercoms will be going too. Just because the frequency is quiet, doesn't mean the workload is low.
It's not as easy to arrange as it used to be, but if you haven't done so already, do go and visit ATC........They're all very friendly folk who like chatting with pilots.........Honestly.