In the new UI, when searching for a title, the results do not display the call number in either the holdings summary on the left, or the general Information box on the right. yes, it's only a click away in the 'Holdings' option, but when you're doing a task involving a lit of, say, 200 items, that's 200 extra clicks.
the General information box already shows Material Type, ISBN, Edition, Brief level 10, and a whole lot of other things, so why not the call number?