The online help manual for the Google Nexus 4 has been revised. Previously, the manual mentioned that some accessories like mice or a keyboard would require an adapter to be connected to the phone via a USB connection. Now, the manual states that a mouse, keyboard, joy stick or other input device will connect to the phone via Bluetooth, just like you would use with a PC, and that USB is not supported for connecting such accessories on the Google Nexus 4. The problem there, according to the online support page, is that supporting a mouse on your Google Nexus 4 via Bluetooth could result in an significant additional drain on your battery. Just what you need, an addition drain on your power cell.
The lack of USB support could throw a wrench into the plans of some Google Nexus 4 owners who were planning on augmenting the 8GB or 16GB native storage on the phone by using a flash drive. With no microSD slot on the device, using a flash drive seemed a great way to expand the amount of native storage on the phone. But without USB support, that dog won't hunt.