This guy is probably merching kodai wands. He's not mentioning the fact kodai is only good in situations involving bursting for slayer while ancestral is superior in all situations with magic, such as with a trident or a sanguinesti staff. He's also using Eternals and a Master Wand to bump up the cost of Set 1 while casually avoiding a non slayer task setup so as not to add onto the cost. For instance, assuming just the weapon and cape for Set 2 because you're poor while using a full ancestral set for Set 1, you would get equal DPS with each set.

Lastly, the Arcane artificially boosts the price of set 1 significantly despite the fact DPS is almost the same with a Book of Darkness or Malediction Ward. If you buy everything without the Arcane in set 1, your total cost would only be 127m compared to 81m. This 127m is better than the 81m kodai because you can't use a trident with a kodai wand but you can with the ancestrals.

Just buy the ancestral, get a book of darkness and use an ancient staff for bursting. Don't be dumb.