The thing is you can't smoke at your local tavern. Smoking even cigarettes has been pushed to patios at best and laws are coming to push smoking even further away. So designated locations like pubs but for pot are going to become necessary because you will not be able to smoke around other people for risks of second hand smoke.
Still very few (IF ANY) local bars that allow cannabis smoking. Public smoking illegal. I live in Denver. There are a few "clubs" you can go, but you have to become a member and pay a fee. Might be cheaper, but not nearly as cool as a popular b+b would be.