rah

Dafuq are you talking about? It's not the case in the UK. Quoting directly from the page you linked to:

You can benefit from Marriage Allowance if all the following apply:

you’re married or in a civil partnership

...

adaptation to modern times of the scriptures

The scriptures don't adapt, only their interpretation.

Arent these religious ceremonies legally binding?

If you don't know then why are you arguing about it?

Except married couples get legal benefits that actually matter in reality that same-sex couples don't get.

That's not the case in the UK.

So its not a strawman.

It's probably not the case where you live either.

more equivalent legally

This is a straw man. The pope's decision is about a religious issue, not a legal issue.