The 45/1.8 is a lens that I very rarely use. It’s not that it does not perform well. It does, and it does extremely so. It is also not the angle of view. In fact the 90mm (eq) focal length is what I find most satisfying for street photography. At that focal length the size of the frame best matches my area of attention. Seeing with the 45/1.8 is completely effortless.
No, it’s the same reason why I tend to prefer the 17/1.8 over the 25/1.8: metal over plastic. Stupid, huh?