Congrats to Brian O'Neill for winning it all!
There was a really good example of when it's useful to add a ball to another player: in the quarterfinals group 4, after "normal" play had concluded, Jay Collins was low man with less than 10M on Tron. Billy had the 3rd place score, meaning that the standings at that moment were Mark 6, Billy 6, Derek 5 and Jay 4. Derek thus stood to be eliminated. Derek used a "heal player" card on Jay to give him one additional ball. Derek was hoping that Jay would score enough to pass Billy but not enough to pass him. Passing Billy would produce the 6-5-5-5 result you see, thus getting Derek into a tiebreaker with a chance to move on. Note that in this particular instance, if Jay also passed Mark, Derek still gets a tiebreaker, since now Jay is the player with 6 and Mark drops to 5. As long as Jay passes one or both of Billy and Mark but doesn't catch Derek, Derek is in a tiebreaker. And, of course, Jay will play fully motivated since this also gives him a chance to get in that otherwise he wouldn't have. The getting into the tiebreaker part worked; alas for Derek, he didn't win the tiebreaker - - Jay made the most of the opportunity by winning the game on Paragon.
Sidebar note and caution for future players: beware the "frozen card hand". As in a set of cards containing two invert cards and not much else of use. One invert is a great opportunity - - swap for something better. Two stops you - - if you use one, the player you swap with gets your hand and the other inversion card, and seeing that there's little to use there, they'll likely swap right back.