This isn't what prioritizing throughput actually looks like in most scenarios.

In the example you gave the amount of read speed the user needs to keep up with a video is meager and greater read speed is meaningless beyond maintaining a small buffer.

You in fact notice more if your process is sometimes starved of CPU IO memory was waiting on swap etc. Conversely you would in most cases not notice near so much if the entire thing got slower even much slower if it's meager resources were quickly available to the thing you are doing right now.