I was digging through the comments for exactly this, thanks!

ChatGPT is human enough sounding for the registration forms. I’ve got no idea why folks think this is the end-all solution when it could be faked just as easily.

A simple deterrent for this could be to “hide” some information in the rules and request that information in the registration form. Not only are you ensuring that your users have at least skimmed the rules, you’re also raising the bar of difficulty for spammers using LLMs to generate human-sounding applications for your instance. Granted it’s only a minor deterrent, this does nothing if the adversary is highly motivated, but then again the same can be said of a lot of anti-spammer solutions. :)

There’s that “just” again. :)

buy and mail checks, balance your checkbook, and go in person to buy things, go to the bank, or get service

It’s simply unrealistic to expect your average American to add all of this (and much more) to their routine and expect the benefit of ditching the smartphone to somehow outweigh the additional time and energy investment. Going in-person for anything in an average American city these days is far more of a hassle than it was “back then”. This is at least partially due to the fact that our cities are built with cars in mind and not people, but that’s a rant for another day.

I’m not sure what can be done on a smartphone that cannot be done on a computer.

Basically any form of two-factor authentication which is becoming increasingly more common and necessary for the average user to access anything from banking to employee services. Sure there are desktop 2FA programs that you can use in certain scenarios, but using these is often bad practice and defeats the purpose of even having 2FA in the first place.

Certain food or delivery services require you to use a mobile app to interact with them. Whether or not these services are essential or not depends entirely on the needs and circumstances of the individual.

I know you mean well but this is kind of a privileged take. Not everyone who wants to disconnect can afford to. It’s kind of like how many people can’t afford to just not use the internet, without it they will likely lose access to many essential resources.

“Just” not using a smartphone is viable for an increasingly vanishing portion of the population, in the US at least.