Actually, users can if they wish... it's just that some parts of the
project explorer can get more cluttered than the pydev package explorer
for users that just want the python-side of things...
e.g.: there are many filters in the project explorer that may not be
interesting for users that just care about python... also, in the long
term I may have some special things such as the package explorer has for
java -- e.g.: refactor menu, build path, etc.
Also, I've just checked that even in the project explorer, my custom items
(that adapt to IResource -- by themselves and with a registered factory --
which works for all the team menus such as 'run as', team, etc) don't show
the mylar items (mark as landmark / make less interesting), so, pydev
users are currently bounded only to the navigator...