Yeah, their main differentiator is that they’re locked down.

and are most peoples 2fa device

They're locked down through technological measures such as sandboxing, which is designed to resist against malicious guests regardless of their origin and distribution method.

With typical usage they contain more sensitive data and people are less aware of what happens in them than PCs.

And mobile phones are perfect spying devices too. So the security question is more delicate

Well, not really. Usually people have all their personal data on their PC, rather than mobile phone.

Maybe this is changing for young people, but on my parents hard drive (for example) there is 30+ years of all sort of personal data, documents of every kind, emails, documents, etc. Not counting all the password and access saved in the browser itself.

If we talk about businesses, public administrations, hospitals basically everything is inside computers, including very sensitive data.

The location data from your PC, for example, is not nearly as sensitive as a phone.