Even bananas and cucumbers and things that don’t need plastic?

Cucumbers, like many other foods, are wrapped in plastic because they last longer that way. Less spoilage comes with many obvious benefits, like not needing to produce/transport as many, which reduces greenhouse gas emissions. Of course, nothing in life comes free of tradeoffs. Pick your poison.

I don't think I've ever seen a plastic wrapped banana in the store, but it is documented that wrapping bananas in plastic also slows their rate of decay, so no doubt the calculus leans towards plastic in some situations as well.