I do find it quite useful. Had one game, at least to confirm general trends, it is gives useful feeback on if you are doing the right thing or not. As you say it is not perfect, the big one being as you say it should keep a record of the number of turnovers you give up on d6 rolls.
Seeing how many injury rolls you give up, or what the armour break % is can be quite helpful. Clearly when the injuries happen is important too, but a general guide.
Clearly there are rolls which are a lot more important than others, and when they come up is important too.
Being 3/10 of KO rolls is either a bit unlucky or it could be a complete disaster as you hae 3 players KOed for much of hte match who fail multiple rolls then make the one before T16.
As I have said before I find it difficult sometimes to see if I have been lucky or outplayed my opponent with a win etc.