I've seen enough posts from people confused about this, even after the Alt-key explanation, to believe there may be an audience that can use this app...I haven't seen it yet (RULE #1: Always post screen shots!!) so can't just usability, but the general idea could be useful...

Loaded...easy to use, but the keyboard image is too small! Would really help if it was enlarged....make the keys/text much larger and it will be much easier to read/use.