It turns those 1/1 goblin tokens into mana when you need it, allowing you to ramp out your big threats or have multiple plays on a single turn
In Commander, you are probably running Lathril, Blade of the Elves
Since infect puts -1/-1 counters on creatures it deals damage to, this allows Yawgmoth to act as removal so long as you have a sacrifice outlet
Its difficult to target thanks to the ward ability and will produce a powerful army of orcs on its own, which is a focus of Sauron, the Dark Lord in Commander
And with Menace, you also have a creature that can sneak through defenses to get in some damage and activate abilities that require something to be unblocked
It can be rough exposing your land drop to anything that kills a 1/1 creature, but the trick is to use Dryad Arbors versatility to your advantage and find clever ways to get it into play, and ways to use the body once it's there