This is fairly useless IMO. As the article itself states "the ideal screen size for a 4K video is 25 feet". So for 99.99% of YouTube viewers this will *never* be taken advantage and is really just a waste of extra bandwidth. So we're left wondering *why* they did this instead of, say, removing the time limits (10 mins) which are pointless now that they have automatic copyrighted material detection. Or increasing the size limits, which would be necessary to make 4k resolution videos practical for any length of time (you'll fill up 2GB file size at 4k in just a minute or two of footage, depending on compression).
So yes, *why*. One Youtube commenter asks an interesting question: "Does Google have plans to stream movies to movie theaters?". Who knows. Maybe this is just for sheer novelty and press worthiness.
- Oshyan