Musical interpretation...but Penny, you played it wrong!

I think of sheet music as a guide, rather than a law, particularly with the video sheet music. Playing 'what's written' is difficult because:

1. If I were to actually put all the notes and strange rhythms in the videos, it would be too complicated to read.
2. I play differently from day to day. If I'm feeling hyper, there are a lot of weird trilly things. If I'm nostalgic, many notes are held through the rests.
3. I change my mind. Making the videos takes some time and by the time I do it and post it up, I have changed my mind on playing and can't be bothered to change the video.

Also, the computer can play accurately and that is nice for the background music as I can rely on it being constant...but as a human, I like to take musical risks and 'interpret' the music, not just reproduce it, perfectly (often very imperfectly).

In the Baroque period, most music didn't include trills and stuff, that was the performers job, to add the right ones. Partially due to the fact that reproducing music was difficult and often by hand, so it had to be written in short form. With the videos streaming by, it's kind of the same situation. If I were to write it out long, it would go by too fast and be difficult to read...so I simplify and leave it up to the performer to make of it what they will. Also, by keeping it simpler, different levels of players can be accommodated. Beginners can read it very strictly and very advanced players can use it for a reference, then make stuff up.