The Nexus 7 was practically announced at CES in January, but a few things changed by the time Google officially announced it a week ago. Being the launch platform for Android 4.1 Jelly Bean was definitely one of those things, and another was the fact that the Nexus 7 isn’t really a tablet – it’s a 7-inch media player.

To clarify, the Nexus 7 is running the phone version of Android. This is most easily noticeable by looking at the status bar, which is split into a button bar at the bottom and a status bar at the top, the latter of which you pull down to access the new notifications in Jelly Bean. Tablets on the other hand merge these two into a single bar at the bottom, which has buttons on the left and a system tray on the right, where you can click the clock area to bring up an expanded status menu that shares at least some similarities to the notification bar on phones.

Like phones, and very much unlike tablets, the Nexus 7 is also locked to portrait mode while on the home screen, unless you replace the launcher. Put simply, it’s a 7-inch phone without the phone parts, making it a 7-inch media player that has a lot in common with devices like the Samsung Galaxy Player.

So why did Google choose to make its own tablet a not-tablet? Owning a 7-inch Android tablet that is actually a tablet, I think I can answer that: Android’s tablet UI was never designed for 7-inch devices. Literally, since the initial Honeycomb 3.0 and 3.1 releases didn’t work on screens that small, there was a months-long wait for 7-inch tablets that coincided with the Android 3.2 release. Perhaps the most famous example is the HTC Flyer, which released with Gingerbread.

Even now that it’s technically supported, 7-inch Android devices are tricky. Notifications are a major pain on some devices, because the tablet UI puts individual notifications in the status bar for each notification. Try updating a couple of dozen apps on Honeycomb – I dare you. You’ll end up rebooting the device to get rid of the notifications. With these notification icons on the status bar you’re also limited as to how many you can display at a time, which is a real pain in portrait mode on 1024 x 600 pixel 7-inch devices running with a virtual PPI of 160, as you basically have room for two such icons, and then the rest are hidden. All in all, it’s a pain to deal with notifications on tablets.

Since notifications are a big deal in Jelly Bean, I understand Google perfectly for wanting its showroom device to show the best version of that notification system. While it has been confirmed that the new notifications work to some degree using the tablet UI, I don’t think I’m being too subjective when I say that people will prefer the drag-down menu from the phone version.

As for the rotation, 7-inch devices really do work the best in portrait mode if you ask me. Their size makes them very book-like, which again means they’re perfect for reading books, comics, magazines. It was no surprise that Amazon chose the 7-inch form factor for the Fire, but unfortunately it cut costs in one area it shouldn’t have: the resolution. I have been reading papers, documents, and magazines on mobile devices since the 400Mhz 480 x 800 pixel Nokia N800, and I can tell you in no uncertain terms that 768 x 1024 pixels is the absolute lowest resolution you can read A4 formatted content without zooming and panning. The Kindle Fire is 600 x 1024, which is simply too low, and that’s been one of the device’s biggest complaints. The Nexus 7 is fronting the Google Play magazine offering, and I can almost guarantee you that if it hadn’t been for that feature, the Nexus 7′s screen would have been 600 x 1024 as well, to save costs.

When you sum all this up, it makes sense for the Nexus 7 to be sold as a portrait device. It’s a digital book, and rightly so. Having both a 9.7-inch iPad 2 and a 7-inch Galaxy Tab 7.0 Plus, I’m in the camp that believes that 7-inch tablets are different enough from 10-inch ones to justify their existence, and I even hope that the rumors of a 7-inch iPad are true.