The Levoit filters are twice as expensive to replace.
The Levoit uses 1 filter "unit", and filters are $55 for a 2-pack on Amazon ($27.5/ea), or half that if you trust the third-party ones.
Levoit recommends to replace the filters every 6-8 months, so you could get 12-16 months of filtration for $55. I can't find any calculation in the article for how long the author estimates their filters would last.
Levoit filters are advertised as lasting 6–8 months and cost $23 each.
Meanwhile a set of four filters like the one in the tutorial cost $70 and looking up comparables online at that price point indicates they're good for 3 months.
So even if using 4 at a time extends to 12 months, that's still more expensive than the up-to-2 Levoit filters you'd use in that time.
I see zero cost benefit here over Levoit -- it seems to be more expensive actually?
The CR box is tremendous overkill for something like an apartment. It's gigantic and I don't even know where most people would put one even in a house.
But it's also not what the original post was talking about. The original post is a device akin to a Levoit in terms of size and power.