Is it good or bad to play photography and choose a mirror to travel around the world?

Walking around the world in one mirror is mostly a lens with a wide zoom range, such as18/13518/200 24/240. The advantages are wide focal length and viewing angle range, large creative space, and simplified equipment weight when shooting.

However, the shortcomings are also obvious. The aperture is too small (the numerical value is 3.5) and mostly floating, which means that the aperture will shrink when the focal length is long. Take Canon 18/ 135mm as an example. When the focal length is 135mm, the maximum aperture is only 5.6f.