"ip dhcp use vrf" is to enable/disable the use of VRF configured on the interface receiving the DHCP packet by the IOS DHCP server code when making an allocation.

Since DHCP Relay does not store the incoming VRF info associated with incoming interface, address may be allocated from an address pool which is not associated with a VRF and as a result, clients may not get address from the right pool.

By default, it should be "no ip dhcp use vrf connected". If you don't use vrf, you don't need worry about this command. HTH.