In general it means the thing is attractive because it is shiny, like diamonds. The noun glitter is related. When used for the hotel (which is very common) it can mean that it is very beautiful because of (for example) crystal chandeliers, mirrors, beautiful carpets, etc. It is very extravagant. Of course, glitzy things are usually expensive. It could also be used to describe a movie star or his/her lifestyle also. If someone uses glitzy to be negative, it means there is TOO much shine or glamor. There is so much decoration that it is no longer attractive. Maybe the glitzy decoration is meant to show off how much money the person has, and then it isn't used in positive way.

glitzy [ˈglɪtsɪ] adj glitzier, glitziest Slang showily attractive; flashy or glittery [originally US, probably via Yiddish from German glitzern to glitter]

Like your picture. Glitzy means has shine & sparkles. Generally means fancy, embellished, sophisticated decor, stylish, expensive.