Yeah, I think that is the main selling perk of the Platinum rank as far as I can tell (well, aside from it being a one-time purchase and not recurring, which I guess is a plus if you intend to pay for another membership for multiple years).
I'm sure someone, somewhere can look at numbers and see if the "highlight" actually makes any meaningful difference to story stats, especially against Gold members, which is the other level that gives you review prioritization (and thus allows you to pump stories out faster, which I would imagine could have a bigger impact on gaining readers).