Are you joking? 人間ドック is absolutely more than a "health checkup". Maybe do some reading: https://medical.kameda.com/general/en/ningendock/what/

> The Ningen Dock is a comprehensive health checkup system that includes a battery of tests, including blood tests, chest X-rays, and ultrasound scans, among others as well as advanced diagnostic tests as Magnetic Resonance Imaging (MRI), Computerized Tomography (CT) or Endoscopy. These tests can help detect potential health problems early before they become more serious or difficult to treat.

That is not the same as the annual mandatory health check.

Maybe your employer pays for you to get a more comprehensive checkup by default and you're unaware of this?

But the ones vast majority of population here gets do not include MRI or CT or Endoscopy.

And, _even then_; specific checkups when you're looking for _specific things_ are still very different things than a full-body MRIs.