How Does DHCP Addr. Assignment Required Enhance Security?

[sleepless swan]

In the Cisco WLC DHCP configurations doc, it states that requiring DHCP Addr. Assignment is best practice for security. How can it possibly enhance security when DHCP itself is considered not very secure? 

[MHM Cisco World]

I think the Doc. talk about the client IP get from DHCP, the auth via Radius server some time for more secure need this IP,
it not talk about the WLC-DHCP secure 

[sleepless swan]

So the Radius auth won't work if I disable the DHCP required option?