The download speed where I live is only 1.5 megabits a second. This makes watching videos at any decent resolution a problem when I'm the only one using the net, and impossible when other family members are using it.
Since I watch a lot of tutorial videos, being able to download them to watch offline means not having to pause, buffer, scrub back and forth, repeat.
After using the basic edition for a while, I've just picked up Pro and gave it a try with a 1080p Blender tutorial. The transcoding is excellent and it will be a great help in the future.
Highly recommended.

Update: March 10, 2019. Still loving this app. The registration is worth every penny, and the little elves that transcode the videos on the remote servers have to be fed somehow. I've introduced another family member to the app and they love it, so we'll be donating again today.