Is there a point to VLANing non-VoIP data to separate from VoIP data on a passthrough phone?

Generic question that would apply to any passthrough VoIP device, not any specific brand.

Since there is one cable between patch panel and phone, with all data to the PC passing through, is there a point to put traffic destined for the phone on one VLAN and traffic destined to the PC on another?

LAN is gigabit to the desk, I'm not responding to any detected problems, just "helpful advice" from people who insist that data should be tagged as VoIP or the other kind of data because "that's just the best way to do it".