Why Chassis MAC Address is used when advertising EVPN Type 5 routes

        In case of EVPN Type 5 or IP Prefix routes advertisement why chassis MAC address or router MAC address is used in addition to VXLAN VNI?

I guess VXLAN VNI is working on same principle like MPLS VPN Label i.e. helping egress PE to determine which VRF/VPN to consult before forwarding packet to CE or end-host. Isn't the VXLAN VNI is sufficient to help the LEAF to determine which VRF to look for and then do destination lookup. Thanks !