Why Ethernet wins
An Ethernet cable gives one device a dedicated link. Wi-Fi shares radio airtime with every nearby network and device, weakens through walls and distance, and suffers interference. The result is lower speed, higher and less consistent latency, and more chance of lost packets.
When it matters most
Gaming, video calls, streaming to a TV, working from a desk, and any device that stays in one place. Use cables for those and keep Wi-Fi for phones, tablets and laptops that move.
Compare them yourself
Run a WiFi Ping test on Wi-Fi and label it Wi-Fi, then run one over Ethernet and label it Ethernet. The comparison tool in History puts the two side by side, including responsiveness and stability. If Ethernet is far better, your Wi-Fi is worth improving.
Making Ethernet practical
Use quality Cat 5e or Cat 6 cable. If running cable is hard, powerline adapters or MoCA can help, though results vary. Where nothing wired is possible, place the router closer or add a wired access point.