The release notes discuss keywords in the photo library, as does the video and the user manual. So, the new release does add functionality for the photo library. Please let me know how my descriptions could be better.
As far as showing keywords in Info, the info panel only shows keywords if the image has them. As a rule, I avoid showing blank lines in the metadata area. You can set keywords in Photos, and in Nitro (as mentioned in the video etc), you can view, filter, and make smart albums.
If you have a situation where an image in the Photo library has keywords and Nitro does not show them, please let me know.