It would be great to have access to all old events.
It would help me as a player to improve, if I could see my old results.
Even better if I could take notes to a match-up.
Take pictures of a boardstate to analyse the situation later. Keep track of the decks I played, what I sideboarded, special cards my opponent played.
Save my own decklist that I used in the event (this is especially useful in draft).
All these would be great to become a better Magic player and track my events