Is it quoting POSIX, saying to stick with conventions, and breaking POSIX?
Also, personal preference is command -o option=value rather than command --option=value, which permit to split things like overriding parameters from config file (if any) to how to start the program (with flags, that needs not be in the config file).
command -o option=value
I do not really like -coptional as it does not work with getopt, and try to avoid -crequired for readability.
Beside than that, yes! of course it is good to stick to these fine conventions