It allows people to have the binary anywhere in the PATH, not only where we say it must be. They might have it in /usr/sbin, or /urs/local/sbin.
utilities in /sbin or /usr/sbin are a bit special because some systems are actually setup to not include this in the PATH, and it is not strictly speaking incorrect; outside of utilities typically in sbin and usr/sbin, we should assume that the utility is found in the PATH, or that the utility is missing (or that users should fix the PATH before calling).
It allows people to have the binary anywhere in the PATH, not only where we say it must be. They might have it in /usr/sbin, or /urs/local/sbin.
utilities in /sbin or /usr/sbin are a bit special because some systems are actually setup to not include this in the PATH, and it is not strictly speaking incorrect; outside of utilities typically in sbin and usr/sbin, we should assume that the utility is found in the PATH, or that the utility is missing (or that users should fix the PATH before calling).