Is it really that big of a payoff?
I’d like to say more, but I’m off to a McDonald’s for dinner. Good luck identifying me there, Ronald.

I haven’t touched McDonalds in at least a year.
There is only one I would go to that’s close to my parents house about 90 miles from me.
Maybe I’m missing something. But it takes McDonald’s a bit of time and money to compile such a dossier.
Is it really that big of a payoff?
They only produced the dossier because he asked for it. Yes, there is a cost to collect and track the data, but it is mostly used to track trends and identify people to send marketing offers to.
My local gas station started a loyalty program that gave provide a $2.47 cup of coffee (after tax) for $1.07 if you joined and punched in your phone number on paying. I signed up and got an addtional 5 free coffees. I also get points, but I did not download the app to track that. I just want the $1.40 savings. After about a year of offering this they began requiring you purchase at least $3.49 worth of merchandise to get the the $1.40 savings. I stopped putting my number in as I am not ginving them the info, if I don’t get something for it. One of the clerks asks me everytime to put in my number. I made it clear to the regional manager that I was not happy with the change.
$2.47 for a cup of coffee is still cheaper than the Starbucks knockoffs that proliferate my neighborhood. The gas station is almost across the street from my home.
Not really. You scan the QR code, you fill out your survey, you pay with your phone, you use your "points". All results in a electronic data base built by you.
McDonalds is just collecting it.
And while the personal data is just something that they can sell to the data brokers the big money is in the meta data.
Yes, you are missing the scale of it. Once the computerized system is set up, probably by region or possibly only in one massive data location, all the information is transmitted wirelessly from each of its digital payment systems in each local McDonald's when every customer pays by credit card on online order. Once in the main system, it is automatically compiled by customer and analyzed by a variety of metrics—region, time of day, probable age or sex, typical spending, etc. A few big set-up costs for hardware, software and programming—divided by millions and millions of customers every day of the year.
Companies also build in some ways to measure whether the effects of their targeting are paying for themselves, such as tracking whether a customer's purchases increased as a result of digital ads personally selected to fit his profile.
It's all analyzed by algorithms without much human involvement unless there is a need for the company to study a specific type of behavior in their customer base, such as in a given region (southwest might prefer more Mexican-influenced spices, northeast might pump up the sales of hot chocolate for more months than the South, midwest might like a milder selection of dips, etc).
Companies that don't do data analysis are wasting a lot of money trying to run a one-size-fits-all approach in a huge nation that still has distinct regional variations. That's the general approach to enhanced supply-meets-demand systems. But this McDonald's dossier takes to to a very granular, individual level, to the point where their personalized advertising not only provides what the customer wants, but relentlessly pushes things he didn't know he would want. That is the traditional goal of advertising, but this is way beyond a print ad in a monthly magazine—personalized ads selected by the dossier will show up multiple times a week or a day on his smart phone, computer and digital tv.
The aggregate degree of tracking by almost all mega-corporations is becoming scary, due to their personally predictive models such as the McD's one described in the opening post. It's as if the local police could know when to stake out a given customer suspected of a crime by knowing when he would be most likely to show up at McD's or Costco. I'm not saying those companies are doing that or could be subpoenaed to divulge this info, but it's worth thinking about in terms of privacy.