I don't think Plastic of any kind is a good idea for wra
If you think about plastic,its like putting your fave thing in a bag to SWEAT!
it creates condensation and the item, be it a Hoover or anything else needs to breath
Metal doesn't take too kindly to condensation i think, I am not an expert but things need to breath.The idea is too keep the dust out only.
Painted surfaces also need air and i think that's why in the good old days things were covered in cotton sheets for long term storage.Always natural materials.
I cant think it can do well on electric contacts either or windings in the motor getting subjected to condensation.
Condensation is going to happen due to the continual temperature changes on the outside of the plastic wrapping.