Not quite the same thing. The dispensaries are operating illegally. The fact that the states "legalized" it, doesn't mean it isn't illegal. There are plenty of other federal laws that don't have state equivalents outlawing them that are widely understood to be illegal as well.

But what is different are the social norms and expectations. The general agreement that they are legal, makes them defacto legal ... except where the federal jurisdiction matters. But, if there was political appetite for it, federal law enforcement could arrest and prosecute everyone involved in the recreational cannabis business in "legal" states. There is just no political appetite. The Rohrabacher–Farr amendment, though, prohibits this for medical usage (just enforcement, it still is illegal).

Note I do think we should broadly decriminalize (not the same as make fully legal) most drugs, and fully legalize things like cannabis.