Vinegar will dissolve rust and also a very small amount of good metal. Products like Evaporust work by chelation which is a different process that doesn't dissolve the non-rusty metal. If you should ever be unfortunate enough to suffer from heavy metal poisoning, and get treatment for it, then they will treat you with chelation rather than pickling you in acid. It's more gentle. You can drop a piece of rusty steel into Evaporust, check on it a week later and there will be barely any loss of non-rusty steel.
The author of the video claims to have found a simple formula using household chemicals that is as effective as Evaporust, but is much cheaper and also the solution remains effective much longer. That's a pretty bold claim, and if he's right then it's worth knowing about.
Vinegar works, and if that's what you have and you can leave the parts in vinegar for the right amount of time then that's often good enough. But if there were a better method available that doesn't cost any more, wouldn't you want to know?
By the way, for rust removal by acid I recommend citric acid instead of vinegar. They both work, but citric acid smells nicer
Alternatively, you can remove rust by chelation in a molasses and water solution. It's cheap, but very slow.
