Why did my games start working after I plugged in my ethernet cable to my pc?

Earlier today I got a new desk, and unplugged my pc to move around. I was trying to play my games from steam. Some of them wouldn't even launch, and my singer player games were super laggy, and they'd freeze. I realized that I forgot to plug my ethernet cable in, so I plugged it in, and everything is running fine now. Even fallout 4. A single player game ran a lot better than it did without an ethernet cable. I'm not complaining. Just kinda curios.

Why did my games start working after I plugged in my ethernet cable to my pc?
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