Yes, but there are many examples of the general principle. For items, I have to find the item I want on the menus or I have to add it into the source material. That is, I can't easily type in "Rusty bronze key (found in shop)" on my equipment list. As another example: I have a special background option from "The Shackled City" adventure module. I just want to write a note down -- maybe under Feats -- that I have "Sign of Surabar" as an option. Again, I could edit the source t add this as a feat or something, but it's a pain when the only thing I want to do is write a one line on my sheet. Also, on my computer at least there is very noticeable delay with each operation. Now, there is of course a benefit to having PCGen handle things like encumbrance and other rules monkeying. But as it happens I am not so interested in those.
A reason why I'd like an editable format would be so I could change and customize the sheet to my liking. For example, if my character only uses one or two weapons, then I could potentially delete the blank weapon area and use it to write something else.