When traveling, where do you put your jewelry at night in a hotel? You could put it in your suitcase if you intend to store it there or in the in-room safe. But if you want it handy for wearing the next day, where can you put it? It might roll off the night stand or into the sink. Pieces may get separated and take precious time to locate.
Use one of the glasses in the room. It keeps all pieces together and is easy to see. If you use the in-room safe, set the glass in the safe. If not, place it on the dresser or night stand.