Do you...?

Not quite true. We know what allows the Need roll.

“You may only roll Need on an item if your class can equip it and it is considered an upgrade. Having a certain item equipped or in your inventory will prevent you from rolling Need on that item if it is the same item level or lower.”

But we can also infer the intent, with regards to Greed, DE, and Transmog.

Greed and DE are easy – one cannot roll Need on an item that one cannot equip, even though they are vendorable and/or disenchantable. Thus, “Greed” and “DE” are not “upgrades”.

For Transmog, it’s a bit trickier:

It’s also possible Blizz is an inconsistent and lazy company, since they don’t really care to respond to any of these, clear them up, or fix transmog rolls.