Cable management inside a PC. Does it actually affect anything or is it just aesthetic?

Short answer: it affects airflow, long-term reliability, and serviceability. It's not just for photos.

Airflow: Cables routed across the front intake or between the GPU and CPU cooler restrict airflow directly. A messy build can add 3–5°C under load compared to a clean one with proper routing. That matters during sustained workloads.

Dust: Cables that cross airflow paths become dust catchers. Over 12–18 months, accumulated dust on cables near fans reduces airflow further. A clean build stays cleaner for longer.

Serviceability: If you ever need to or want to swap a RAM stick, add storage, or replace a component, a build with cables routed properly takes 10 minutes. A rats' nest takes an hour and risks accidentally disconnecting something else in the process.

The cases where cable management is genuinely aesthetic-only: small form factor builds where there's nowhere to route cables behind the panel anyway. In a mid-tower with a back panel channel, there's no excuse.