So you find yourself in a one of the best museums on the planet but the real image is not of the works of art but the square outside. An advantage of a phone or small camera is that held well it can often fit through a gap in a window. Thus capturing a shot without the risk of reflection, glare, or dirt from shooting through a window. On this occasion I distinctly remember a slightly open window allowing enough space to get a camera through and boom a record shot from Saint Petersburg resulted. Now I'm not saying this is a great photo, that's not the point, but it is a lot better than one shot through the window, or not taken at all.