Also airplanes, satellites etc. The standard now is laser ring gyroscopes as they have no moving parts, are super sensitive, and very light in comparison to older options. Mentour pilot has an episode on how these are used in the 737.
Speaking of which, these seem like the kind of thing that would integrate well, but cell phones are still stuck with gyros/accelerometers/magnetometers that are pretty bad, especially in cities, double especially near buried power lines. The old "my heading spins rapidly in circles whenever I walk on a certain section of sidewalk" problem. Are there engineering challenges to integration or is it a spooky controlled technology conspiracy?
IIRC it's a size and power thing. You can emulate most of what a ring laser gyro does with good accelerometers and that's the better choice for most devices needing long battery life and compact size. Ring laser gyros (while small) are not that small last I checked. A quick google shows you can get them in about the size of a pocket watch. So potentially a good case addon for those that need it without the cost/power usage issues that would hit those that don't.
By "integration" I meant "turn the module into a chip" rather than "put the module in a phone" -- though your point about power could be the answer. Some lasers and optics just feel like the kind of thing that a clever team could squeeze onto a wafer, maybe with a loop in the third dimension. Or maybe just require two of them. There's probably a good answer as to why that's harder than it seems, I just don't know what it is.
https://en.wikipedia.org/wiki/Ring_laser_gyroscope