Windows 7 - Does compatibility mode actually do anything?

So far, I have yet to have compatibility mode solve a single problem. Has anyone actually seen it do anything good?

Now running XP mode in virtual works and is an awsome feature. But compatibility mode? Not so much.

Yes, I've used compatibilty mode to install drivers and applications. I bought a DB9-USB adapter, and in order to get it and the application (an old Pronto remote control application) working in 7, I needed compatibility mode to get everything installed.

Yes it works and is valuable. I could not find a printer driver from HP, for 7. I downloaded one for XP, went to compatiblity mode and now I have a printer.

It takes patience and some persistence, trying each mode backwards (I got a friend's expensive old Acer slide scanner to work in 98 mode) and making sure the .exe file holds the mode, as Administrator if necessary

Sometimes, in games for example, you need to make both the installation .exe and the game player .exe in the same compatibility mode.

Drivers are the trickiest since not all drivers come in executable installers. How do others get drivers to run in another mode?