As part of the article and video they discuss the differences between the three types of uncirculated commemorative coin finish: Proof, Brilliant Uncirculated, and Bullion. For the Royal Mint, proof are the highest standards followed by brilliant uncirculated then bullion.
While this may be intuitive to experienced collectors, novice and new collectors may be confused by the difference. The Royal Mint does a very good job at explaining the difference in a short, well produced video. It should be interesting to the beginning and expert collector to see how another mint does their work.