This gives a reason why MWI is not a useful object of study.

Well, not quite. Someone ought to be thinking about this sort of stuff, and the claim that link makes is that MWI isn't worth considering because it goes against the "scientific ethos."

The reason I would tell people why MWI is not a useful object of study (for them) is because until you make it a disagreement about the territory, disagreeing about maps cashes out as squabbling. How you interpret QM should not matter, so don't waste time on it.