Let put ourselves on the shoe of the owner. In my cognitive evaluation on veracity of bitcoin popularity and numbers there is a big market if I do accept bitcoin as payment and option for a better marketing strategy but the government is not declaring it legal and how would do I compute the taxation.
This would be the thing that would make this stuff complicated because speaking of legality and taxation this would be the main concern if you do have a supermarket and lets say you are the owner but one thing that hesitates to implement or offer such thing would really vary on the decision that would be made on the government which you are on.If you decide to accept it but they decline such request then you cant do anything about it.I have heard some supermarket do accept bitcoin but i actually forgot it though.
Yes thats it, the owner of that supermarket is dependent on the nature of the law they were govern by it. We know how politics work and I know in time this things would be better for the bitcoin community but until when that this adaptation be feel by every bitcoiners is a question only time can tell.