Zend certified PHP/Magento developer

Disabling X-Magento-Vary for customer groups Varnish cache

We have no differing content on our web pages for logged in and not logged in customers.

With the exception of a small drop down menu showing log out/my account.

Would disabling X-Magento-Vary cookie for logged in customers have any impact on site functionality? As it seems such a waste of resources and poor experience for the customer to have no page varnish cache when they log in and browse the site, when the content is identical.

We don’t see it feasible or efficient to warm the cache per customer group.

How would you go about doing this?

It’s same for currency change… Why does the whole page need recaching? why can’t the product prices just be hole punched? and page cache remains consistent.

Any help appreciated.