Please have a look to the
definition of Portable ApplicationOf course, whatever you do with a USB Key can be done with a flash or local hard drive and depends on your needs.
e.g personnally, I do not need to put it on an USB Key because I have only one computer and I do not need to use Liberkey elsewhere, so I copied it on a local drive but if you are technician and wanted to help some collegues or friends without installing any particular software in the collegues's computer, you can simply use the ones from your Liberkey (copied on your usb-key) and that's all ! (faster, easier !)
Liberkey is not supported under HTC (more commonly not supported under cell phones) and I have personanlly some doubts that lots of application are useable on an HTC, but well why not ?