Why morden buildings with Glass and exterior Lights are not eco-friendly and waste energy?

I have been visiting lot of places across the globe and get surprised to see buildings with lot of Glass panes. Good exterior decor with lot of lights.. example recent Effiel Tower Power shutdown for 5 mins to demonstrate conserving energy.

I feel Glass gets heated faster and thus consumes more energy as Airconditioner will consume more energy to keep the same temp.

Exterior lights and decor are superficial. They provide majestic looks to oriental structures but still I feel now a days Architects are not educating their tenants about such things.