I think this is a good idea, but it might be hard because when you shop in the general store (like daily needs market, or clothing shop), you are talking only to the worker there, not the manager or the decision maker of that store or company or vendor, and they don't have much power to be heard by their boss. In my opinion, this idea can be applied to a bigger store/company/vendor like car companies, or bike companies, real estate/property companies or else, because when we go shop or want to buy in this kind of shop, they see us as a potential buyer and will find a way to make us buy their product. Loan, credit, cash, or else, and maybe when we ask if they accept bitcoin or not, they will ask to their boss. So this idea might work.
But for me, the comfortable idea for now is to advertise it on our social media. It is easy and it helps a lot if you make it right. People who follows you will gain some awareness and at some point will ask you about it. With this simple action, it does a lot of impact to people about bitcoin and cryptocurrency.