It is mandatory to configure client provisioning policy and portal irrespective of whether or not you use redirect or redirect less posture since it is required to push any updates to the posture profile/AnyConnect updates etc.. However, whether or not you would like to redirect the clients to CPP is a different story altogether. If you do not configure CPP, if all the configurations are pushed from SCCM or some other way to the client machines, an admin should be doing the same manually every time to make any changes.
