And another point, I don't want anyone, even the merchant, to know I am paying in Bitcoin.
From a reply I just made:
Yeah, great point. 'Right to pay privately' - even the merchant may not need to know that you are paying in Bitcoin.
I've been there- you ask to pay in Bitcoin - and you can see the value judgment in the eyes of the clerk, even though they are trying to hide it. And since you've outed yourself- they look at you differently, every time you go into the shop.