I haven't gotten a chance to watch the video you've posted because my data is acting really wonky at the moment...
However, rooting is different than replacing the brakes on your car. The example you provided was replacing one piece of hardware and having a different unrelated piece break.
Rooting the phone gives you access to just about anything, including overriding limits set in place by the manufacturer.If you dont know what youre doing you could potentially damage quite a few seemingly unrelated pieces of hardware.Overclocking could cause damage the CPU and other damage from increased heat, increasing max volume could damage speakers, overclocking GPU could damage it, ect. The list really can get quite long.
As far as whether root voids your warranty, I'd have to default to asking your manufacturer, carrier, and insurance company. Ultimately its going to be buried in your terms and conditions with them.