Technology

It costs less with the app bexause you pay with your privacy and dignity. Now tgey can A/B test your behavioural patterns like a lab rat and create models to tweedle your knobs just right for optimal value extraction at the specified satisfaction level of you type or personnal prifile.

Then they can use what they learned against non-app users that are also human. It won't be as accurate but they'll probably guess your profile type just from environmental and anonymizer data footprint.

From tge cctv camera, gait tracking, face recognition, automatic demographic analysis, the car model and plate number you came with, your vocabulary grade when talking to the clerk and of cpurse the treasure throve of data they can buy from your credit card company, they'll be able to know you as well as if you had the app. They might even end up knowing you better than yourself.

Pocket computer, phone is just an aspect of it. Surveillance capitalism monitors is what they are in the context you describe