@The:
I'm thinking inanimate objects can only "eat" Zoan DF. Would be insane though if they could "eat" Logia and Paramecia too. Instead of the wielder having a DF, the item he/she wields does. Like…imagine if Whitebeard didn't have a DF, but, his weapon did.
Well a sword made of rubber (yay!) or a intangible clock don't seem to far fetched but Im with you on the Zoan part, there has to be a reason for the fact that all the objects who've eaten DFs are actually zoan.