If by “strict reading” you mean “any reading at all”, I would agree.
I’m not sure how the legal power to say “the unit of mass called the ‘gram’ shall be defined as the mass of a cube of pure water, one centimeter on each side” allows you to say “anybody that manufactures a phone must include the following physical and logical features.” If you go off that definition, you’re basically ceding pretty much unlimited power to the government.
For phones, you’re right.
For cars, we have public metering devices that measure units of stuff and charge money. This makes it fall into the category of metering devices used in trade. And we do regulate those almost universally. You can’t just put a different shape nozzle on a gas pump, for instance.