I don't think that's what the author was getting at here - a compelling reason is that the value of the payout to fix your own car x the probability of it happening is lower than the total premium extra. Eg the "Insurance is only worth it for things you can't afford" mentality.
This also checks with the OP in this subthread: The insurance seller will always push for more coverage for self-interested reasons.
That's opposite my experience: I took an appointment a few weeks ago from my insurance agent (Texas) who wanted to review my existing insurance vs my needs. On the call I laid out that same logic -- I can afford repairs to my car out of pocket, so it doesn't make sense to insure it, so maybe I should drop it (just keep liability) -- and she agreed, and was happy to tell me the savings!
(I didn't go through with it on the call and maybe she would have put up resistance then, so who knows.)
Edit: From reading the source, it seems like the author didn't clarify that that was the logic he was using, or that he could afford the damage to his car out of pocket. Insurers are probably accustomed to people overextending themselves and skimping on insurance without being able to afford such things, which is risky and something agents have to head off early on.
Salespeople have different strategies, so you aren't always going to get one who tries to sell you a bunch of stuff you don't need.
Some will try to milk you for all you're worth. Others will try to stick to things that you plausibly need and hope that selling to more people and having a higher renewal rate will make up for the extra amount that they aren't squeezing out of each person.
This also checks with the OP in this subthread: The insurance seller will always push for more coverage for self-interested reasons.