Youre gaining an extra card in your hand, potentially finding what you need for your strategy, and developing a 4|4 body on the board
Modal cards, which we've had in Magic for decades, are almost always a bit better than they look at first glance since they offer options
Attack with a creature, like Gonti, copy the myriad trigger with Strionic Resonator (since myriad says Whenever) to get double the attacking tokens, and then Panharmonicon gives you double for the attacking creatures
Additionally, there are still ways to get rid of Indestructible cards - they aren't totally immortal
Summary Abzan commanders offer a variety of playstyles, synergizing with graveyards, counters, and enchantments
One of the best Jund cards in sacrifice-based decks, Korvold grows fairly large and draws you many cards, and its good enough to see Commander and 1v1 Constructed play in Jund decks