Haven't seen this too much since Azelf LA (so people could know their prizes accurately). It's not too common as the TCG needs to be played at a much faster pace opposed to the VG as it takes much more time (imagine VG BO3 50 min +3 lol).
I do think it gives advantages only in a BO3 game scenario. For one, you know all the specific card counts. While some things are obvious, you might not immediately notice if your opponent runs 3 or 4 spirit link, how much energy was played, counts on Lysandre/Birch, etc. Knowing your opponent's deck is crucial late game when you have to think of the odds of them having specific cards.
At the same time, if you want to be the guy that takes games to time and accepts a lot of criticism, then do this. I don't think many people want to be playing against a person who not only knows your entire deck from playing it, but from writing it down as well. It can be shared all over and any any secret deck's chances of Top Cut are wiped out by that guy. Also, writing down everything can lead to misplays. If you are too focused on writing and not gamestate, you can miss things.