This section lists the "best practice" SMB requests -- ones that would permit a client to exercise full CIFS functionality and optimum performance when interoperating with a server speaking the latest dialect as of this writing ("NT LM 0.12").
Note that, as of this writing, no existing client restricts itself to only these requests, so no useful server can be written that supports just them. The classification is provided so that future clients will be written to permit future servers to be simpler.