I mean if they are improving the quality a bit even for a casual streamer
The sad thing is they aren't improving the quality at all, they're pretty much reducing it.
By blowing up the image from 4:3 to 16:9, then upscaling it to 4k, all they are really doing is blowing up the flaws in the video. The resulting videos are a blocky mess with bad framing.
They also insist on posting videos shot at 25-30fps at 60fps, which means computer predicted in-between frames that make the videos look like a cheesy 90s soap opera.
If they really wanted to do a good job, they could run a little clean up and a 4k upscale on the videos while maintaining the original aspect ratio and frame rate.... But most 4k capable TVs and computers will do that automatically for you better then whatever program they are using to upscale these videos. So like I said, you're better off finding the original video they downloaded off Youtube.