Various arguments for wiring your home with Cat 6 (gigabit) ethernet or better.
Bottom-line advantages of Cat 6 over 802.11ac WiFi:
- Better capacity. While 802.11ac, under optimal conditions, can approach 500 Mbps, having a wired connection that guarantees 1000 Mbps can be useful.
- Better reliability.
- Better security.
- Better latency.
All of this said, it isn't either-or -- you can use your wired connections for connecting computers to NAS or when you need maximum speed for uploading.