"me thinks until real asset value behind the coin will never...

"me thinks until real asset value behind the coin will never receive any credibility"

If by real, you mean that it places an entry on the publicly available database to a another asset? That's called custodianship. That capability has existed for thousands of years and is nothing new.

"will never receive any credibility"

They're worth $AU5,977 each. I bought my first ones I think at about $AU117. How's that credibility? Or we could look at the fact that if you linked to an extrinsic physical asset, the asset could be seized. In Australia, this threat vector is very real. I know of a number of people who have had their own assets (That they actually completely owned) seized by the Family Court regime. With Bitcoin, you can have complete command of the good via an encrypted wallet, or you could go further. You could even just remember 12 words (In order), and no physical or digital holding is even required to be maintained. This is its credibility.

"now back to the debate is this a store of value or a method of payment"

It's both, and is used as both by people everyday.