Eh, the comparison(s) do their job. There are enough differences, most of the time, to justify them. And that is the case for ROTTR as well. You don't need to see them in person. Would it be better? Certainly. But it's not necessary.
I wouldn't say it's necessary but IMO the videos never ever do it justice and frankly it's not even close. I'll never forget watching BF4 videos online and thinking graphically the game looked ok but I was more in it for the gameplay. Got the actual game and watched it on my TV and I went from thinking the graphics were ok to looking very good. I pretty much stopped watching all videos online for graphical comparisons after that.