Like Minds Eye, its a scalable effect where you can control the investment you put into it
The meta as it is right now is influenced by some fast decks that push others out, but this can change with the printing of new cards and bannings
I did a little research and found out that the official capacity of an Elite Trainer Box with sleeves is 500 cards
This went very well, being able to hit for enough damage each turn to go somewhere around 6-2 for each game, but sometimes running into problems with those pesky water decks
A creature with Vigilance can relentlessly attack while still being available to defend when needed, doubling their usefulness
Card draw is another reward, often connected to paying mana, like with Shanna, Purifying Blade, Well of Lost Dreams, or Dawn of Hope