Smart used as expensive, why?

I sometimes see phrases like "smart hotel", "smart restaurant" (especially in guide books). From context I usually understand it as "expensive but worthy". Is it correct understanding? Why is word "smart" used? I rarely see it used in that way outside of this context. I never heard "smart car" in that sense for example.

Edit: Example of usage (that actually encouraged me to ask this question), this is quote from guide book about Morocco: "However, it is a waste of time trying to negotiate at peak of the high season, or in the very smart hotels, such as the La Mamounia in Marrakech". So it is even used in comparative form. Apparently this La Mamounia Hotel is one of the most luxurious and expensive hotels in Marrakech.

The emphasis is not so much on its cost as on its desirability. The definition given in Oxford Dictionaries Online is ‘(of a place) fashionable and upmarket’.

Smart is used as praise here, with secondary meanings. A smart hotel would be trendy, fashionable, clever in some way, or artistic, possibly also in good location in an area that also shares these traits. It's a very liberal, artistic use of the word smart. It imparts a kind of excitement about the subject, and youth, and approval. It does not necessarily mean "expensive", though a "smart _" would be desirable and thus demand for it would tend to increase, and thus its price. It would be odd to find "smart" used in this way outside of some kind review, such as your guidebook. It is a rather rare, literary, poetic way of describing the subject.

"smart car" uses "smart" to refer to advanced/good electronics/other technology & software inside a machine or other object, a completely different use of the word.