Wi-Fi connects devices over radio waves, so you can move around without cables. Ethernet uses a physical network cable between your device and a router or switch.
In practice, Ethernet is usually faster, more consistent, and lower-latency because the link is dedicated and far less exposed to wireless interference. Wi-Fi wins on convenience for phones, laptops, and rooms where running cable is impractical. Newer Wi-Fi standards have narrowed the gap, but a wired connection still tends to win when gaming, large local file transfers, or rock-steady streaming matter most.
Source: Wi-Fi vs. Ethernet: How Much Better Is a Wired Connection? — How-To Geek