Does "nuitée" mean long "nuit"?
Is it the same as "journée" compared to "jour"?
Je n'entends le mot que dans la bouche des hôteliers ou des loueurs de gîtes de vacances.
Indeed. 'Nuitée' only concerns the hotel industry. The client does not use it. Only the hotel websites, etc. 'Une nuitée' is a night spent in a hotel, but only from their own point of view. The client never says he spent a 'nuitée' in a hotel. The client uses 'nuit'. The synonym of 'nuitée' is 'nuit d'hébergement'.
However, very long ago (and possibly until recently in the country), the term was used in the same way as 'journée' for 'jour', 'matinée' for 'matin' and 'soirée' for 'soir'. But even the first edition of the Dictionnaire de l'Académie française (1694) says it is rarely used other than for a night you spend in a hotel or similar (when you have to pay for it): http://artflx.uchicago.edu/cgi-bin/dicos/pubdico1look.pl?strippedhw=nuit%C3%A9e. They also say it can mean a night of work, but this meaning is obsolete, as far as I know.
I think that "nuitée" is used to refer to the time for sleeping, or bed-time, while "nuit" is used more for the actual time of day when it is dark outside. "Bonne nuit" is more like a goodbye, kind of like saying "Goodbye and have a nice night" rather than saying "Bonne nuitée," more meaning "Have good dreams."