The simplest explanation I can provide is that it is not a "website", it is a "company" that provides a lot of their services to their customers on a "website".

They are a global company. They need people who know those countries in order to operate there.

The people who build the website are one group of people responsible for managing the company. Who designs the website? Who manages the projects they are working on? Who pays for all of those people? Who interviews new people that they need? Who works in the customer service department? Who sells the services they provide to other clients or companies? Who services their office spaces? Who ensures facilities are restocked for their office workers?

It is a company.

You should presume that anything you type into your keyboard on any website could potentially be captured, saved, processed and read. This is not a security fear, and The teams behind ChatGPT have never admitted to your queries being encrypted in any way.