In short, if you need less than a couple degrees of accuracy, it's going to take a bit of tinkering. I wouldn't trust a $1 sensor for a tropical fish tank, for example, but probably good enough for a home thermostat.
They claim accuracy of +-0.2 c across a wide temperature range and in my use they seem to be. easy to find on a support board for under $10
For power consumption a system power tree needs to be constructed and that will set the bounds that firmware can achieve. That would be better than trusting the manufacturer but a real test is best.
Avg buyer wont read a token of tests before buying whats marketed best.the whole point in test like these is to provide non-average buyer with info average buyer doesnt care for.
Similar reasons: the intended audience isn’t the average person.
You can certainly wreck connectivity with bad and old firmware. Similarly, housing design, PCB thermal isolation, not putting the sensor next to the MCU, measurement averaging settings, etc. all are going to affect accuracy even with the same sensor (particularly dynamic accuracy).
Those who care about the internals are techies who maybe want to build their own or are very curious. Most buyers don't care about that, they care about how well it works in practice. Just like they don't care what RAM chips are used in their phone or computer, what modem, what screen panel, what camera sensor, etc.
I have a bucket of devices which don’t do what I hoped they’d do because they were different from what the reviews said. And not just IoT unfortunately. Some do a better job at flagging these changes, some don’t.
But in the end taking the common case that the product is what it says on the box or that the changes have no impact on how it works, most people don’t care about the name of the chips. Not unless they are very keen on the tech and then there are more tech-oriented niche sites that might provide this.