Have to say, I agree with this.
I wouldn't have up to a week ago, although he has tested himself in Portugal, England, Spain and Italy, the last one I thought was less of a big test, particularly joining the dominant team there. I could also understand Messi's reasoning at this stage of his career, to want to move to France for an easier and confortable footballing life while still challenging for CL and prepping for the WC.
But this (if it comes off) changes my perspective on both those. He would be coming to not only a hard league, but a hard team to play in as an individual for a manager that isn't a fan if ego and wants workhorses. Which he isn't stipid to not know, so he must be prepared to give on both. And reportedly reducing his wages to do so, unlike Messi who hot a better deal than he had at Barcelona. Which I don't and never did have anything against, but worth the comparison.
As you say, very much puts Messi's choice into perspective. All which will make the clash (IF this gets done) when they play even more interesting, worldwide.