>Company data remains secure while employee data remains private, with cryptographic separation of work and personal data on devices.

Does this mean that I'm able to enroll two Apple Accounts on an iPhone at once? Or does Apple actually think that I'm gonna be storing personal data, such as my health data, on a company device with a company-managed Apple Account?

At the moment I just have two iPhones: my personal iPhone that has my data and is connected to my Apple Watch, and my work iPhone, which sits on a desk and does nothing. The separate Apple Account on the work one means that I can't connect it to an Apple Watch and I can't download my apps on it, so you either can't accumulate any personal data on the device, or you need to submit all of your personal data to your employer's Apple Account. Including whatever health data your Apple Watch produces.