It’s all about sharpness and precision. A safety razor simply allows for more precision and control of the blade and safety razor blades themselves are often much sharper than those in cartridges. Alternatively, better could also mean the ability to choose duller blades, which you can’t do with cartridge razors. The use of a single blade also makes rinsing 1,000 times easier, which means never dealing with a clogged three-blade again.