It can tap for mana just like any other land, and in the event that you have seven cards in your hand, you can tap it to draw a card instead
As it costs only two mana and has haste, you'll likely be able to trigger this ability multiple times in the early game, stealing important top-deck pieces from your opponents
This gets weaker the further you stray from mono-green, but I can live with only spending 4 or 5 of the 6 mana my dork provided
The original Ultimatum cycle had some powerful effects, but it was Cruel Ultimatum that left a lasting impressionon the game, on my opponents, even on professional Magic
While its no Sword of Feast and Famine, it still does a lot for a little, which has always been the strength of these equipment
Its a fair amount of text to parse, but in short: when you trigger Gimli to fight, he will be indestructible, so dont worry about it