It can be used while you're on the go, either in the car or on public transport - you could easily stream content from the drive to your phone while the drive is in your bag, for example, just make sure it's password protected. Because it's battery powered, you don't need to plug it in to an outlet, nor do you even have to be at home to use it. It will stream videos, MP3s and photos to Android (version 2.3 or higher) and iOS (version 4.3 or higher) devices.
The main aim of the Wireless Plus is to be a streamer of content to your smartphone or tablet. It does feel a little heavier than a typical 2.5in, portable drive, but that's to be expected with the internal battery and the extra circuitry that it houses. The only physical differences that are noticeable are a power button on the side (one that feels terrible to use as you never know if you've pressed it) and an extra couple of status LEDs on the top - the power LED and the Wi-Fi LED.
It looks like just another portable hard drive from Seagate, complete with a swappable USM (universal storage module) interface. Physically, there is nothing that makes the Wireless Plus immediately stand out from the crowd.