Doesn't make his point invalid though. My battery on my older rMBP was almost dying and I went to the Apple Store to let them replace the battery and they also completely changed the top including the keyboard, because the battery is attached to it.
So if you need to get your keyboard replaced, just ask for a new battery instead.
I have a mbp 2015 retina so same as he has I think, Apple quoted me $500 to change the keyboard but $219 to change the battery which included the topcase.
For newer models, no need to do this since keyboard repairs are free.
So if you need to get your keyboard replaced, just ask for a new battery instead.