You can use GPU for video conversion and video playing.
and when software uses that hardware acceleration then result comes awsome and very fast.
You may convert video format within 3 minutes with the help of GPU, Same Core i7 take it 20 to 25 minutes.
I want to now the names of different software as well as other GPU advantages.
There are very FEW software that have GPU acceleration. In your OP you pretty much listed the main consumer related ones. There are some very specific CUDA based plugin's for CFD/CAD/renderings. Check out the nVidia CUDA page for more info/software.