The defending player chooses and sacrifices the required number of permanents before they declare blockers
The size of these combined with vigilance means theyre always a threat, and if you happen to have this and Diregraf Colossus out then youll likely be getting three Zombies per Zombie, and thats just pure value
It also has some benefit for Goblin tribal decks, and having a color land with ability that can enter the battlefield early in the game untapped is a really nice bonus, too
This places you back at the start of the loop, allowing you to sacrifice the new token to start the chain once more for infinite damage
But actually, this isn't ideal for a couple of reasons Firstly, your opponents can crack their fetchlands in response to Hamlet's triggered ability, making it ineffective against any that are already on the field