Clearing out the garden shed . The bolt-on 'bumper' that the tow bar (with detachable hitch) replaced is sitting there.

Is there any conceivable reason why I might need to keep it?

I kept the one for my old Passat and the garage looked at me "gone out" when I handed it over with the trade in.

Stick it on ebay if you don't intend on swapping it back. Someone wanting to correct a rear-ender may want it.