Are C3 steel bumpers at all effective or strictly decoration?

[Brassplyer]

As thin as they are do they provide any real "bump" protection against anything beyond a shopping cart or bicycle or are they as they appear to be just trim?

Back in the yesteryear my brother in his mid-70's LeMans and me in my '66 Fairlane wagon would horse around bumping each other from behind going down the road at low speed, with at most some surface marring of the bumpers. They would actually absorb a fair amount of energy without apparent damage.

 

[LLC5]

Decoration only, the eurathane bumpers were supposed to absorb a 5mph hit with no damage but that wasn’t the case either.