The regular versions of PSE 10 have the same kind of automatic updating (just go to Help>Updates and let the updater do its thing) that full Photoshop has. You can update the raw converter in the app store version, but since apple requires that everything in app store programs has to live within the app package itself, the file paths are different, so unless adobe updates the whole program so you can update through the app store, the adobe updater doesn't know what to do. You can do it manually, but it's kind of complicated to dig everything out of the adobe update, not as simple as it was in older versions of PSE.
This thread over at the adobe forum gives you the general process for updating the app store version:
http://forums.adobe.com/message/4106312#4106312