Why do we eat plants if we can’t digest cellulose, ie, plant cell wall?

Question

Title says all. Plant cells are covered by cell wall made of cellulose. The human body doesn’t have the enzyme cellulase to digest it, so why do we eat them? Do they just pass through us? If so, why are they ‘healthy’?

In: 55

Answer 1

Why do we buy stuff in cardboard boxes, if we have no use for cardboard boxes?

Perhaps it’s the contents?

Or we move.