Is there a technical advantage(s) to segment voice and data traffic at Layer 3 to their own VRF? I remembered I read it somewhere but I could not find it now.
The advantage of VRF Lite in Voice and Data Scenario is to have separate routing table & whenever you tweak one traffic it won't affect other traffic.
You can use the technology independently like QOS, PBR, etc.
You will get freedom to do any thing with that traffic.