The optics of my 4-inch refractor allow routine use of 150x on some objects. They equate magnification with the ability to see things in the sky, and for the uninitiated, that s what you might expect.
Magnification claims by suppliers of department store telescopes are indeed misleading.
However, effective use of magnification can work to our advantage. There s a long history of identifying a telescope by how much it magnifies. In the 17 th and 18 th Centuries, it was common to refer to a telescope not by the diameter of its objective, but by its length. Charles Messier used many different telescopes, but in some cases we know only their length, not their diameter. Since focal length determines magnification, the length could be used as a proxy for how much the observers were able to magnify the objects they were observing.