OK, here's another reason for an app like this. There are remote control Android apps out there, but there's none nearly as good as the commercial Salling Clicker (
Salling Software - Home). The author of Clicker has declined to support Android for now, because the Bluetooth support is so poor. Clicker also supports Wifi, but that seems inadequate if you want to, for example use it to control a Powerpoint in a "foreign" environment while making presentations on the road. E.g., there might not be a Wifi hotspot handy, much less one that your hosts would permit you to use.
Now, suppose that you could easily establish a Wifi interface between your laptop and your phone, using the software requested by this thread. You could do this on the road, and it wouldn't even require any use of your data plan, so you'd never be accessing the Internet per se.
Yes, I know that Windows 7 supports this functionality (letting you turn your PC into a Wifi hotspot), but that's not universal enough for the Salling Clicker author to release a Wifi-only Android version of his application.
I apologize if my explanation is unclear. If you have questions, feel free to ask.
I don't think that Pdanet will do what I want, but perhaps I am mistaken.