This was a really excellent post, the best I've seen you write up this material, and among your top 5 posts ever.
Having said that, I'm tentatively going to disagree.
I made a conscious, somewhat coerced choice in my early 20s never to rely on revolving credit. A combination of random course-of-business (of course resolved) delinquencies and no history of revolving credit resulted in my having relatively poor credit. Compounding this, my disinvestment from my own credit score has led to a new dispute resolution strategy for e.g. medical billing mistakes, which is "ignore mistakes and disputes forever" --- you can imagine the resulting impact on my credit score.
The net effect on my life has been minimal.
It was comically difficult for me to obtain an actual bona fide credit card (which I wanted in order to broaden my choice of car rental agencies --- a problem that has become less important over time as more and more rental agencies accept debit cards). A few weeks after I got the first wire transfer from the sale of Matasano, calling Chase with a checking account balance that could fairly be called "moronic", I had to argue for about 30 minutes for them to issue me a credit card with an extremely minimal monthly balance.
That's about the extent of my problems.
Every landlord I've rented from has pulled my credit. My credit has always been bad. But my landlord references were spotless, and that's what landlords seemed to care about.
It's more than likely that if I was in a different career, and particularly if that career was in a lower-paying sector where workers have less leverage, my credit score would be a real concern in finding a job. But in this industry, my general response to being declined for a job as an adverse decision relating to my credit score would be to do to the reputation of the hiring firm on Twitter approximately what the lawyers at the Bank of Bigness believe their regulators will do over an FCRA violation.
I would almost certainly have a hard time getting a loan for a car. But then, see "revolving credit". Don't get a loan for a car. I had one once in my 20s and remember it being a pretty miserable experience. Until very recently, every other car I'd driven since was (a) worse than that car and (b) on balance a more pleasant experience for not coming with a Significant Monthly Bill. Obviously, in this industry, you will eventually reach a point in your career and your personal financial maturity where "obtaining what you believe to be a car commensurate with your status" will stop being an interesting problem.
Which, I think, leaves us with home ownership. I don't have a good answer here. I bought my house in 2005, weeks after starting Matasano, a company which for all the intents and purposes of my mortgage lender did not exist. Suffice it to say I was not able to push that lender around with the contents of my bank account, which were in 2005 also "moronic", but in the other direction. I probably got a worse rate. And it was 2005, so it's possible that my only effective qualification for buying a house was "50.0001% likelihood of currently having a pulse".
My tl;dr here though is, at least in my case: if you don't use credit cards ever, your credit score doesn't much matter, and as it turns out credit cards don't much matter either.