When your debugging a large system, your often looking at allot of variables. It would be handy to save and load them or to switch tabs when switching over to another bug where you need other vars.
Now you need to delete all vars and start all over to collect the data to view.

If you can save a list and open it later on again (or leave them at several different tabs) then you can let a bug rest and go debug another one without deleting all watches.