The aim of this kind of deck is to flood the board with a lot of Skeletons, attack in with all of them, and either deal lethal damage, or keep chipping away at your foes while your own army becomes larger and more dangerous
However, we have to talk about the elephant in the room, the take-back
Sideboard highlights With the deck itself being a straightforward, finely-tuned machine, the sideboard brings in some variety as well as potential answers
I like this in any Commander deck with a Commander with a combat damage trigger, like Medomai the Ageless, since you will be including things like Whispersilk Cloak and Rogue's Passage to kill in one hit already
Especially if you are willing to sacrifice NM condition and go for cards that are SP or lower