Accessibility guidelines usually allow them but encourage you to make it a last resort.
I have a Lenovo yoga, and its a constant nightmare of websites and apps that cannot figure out if I am a laptop or a tablet, even with tablet-mode fully off. I am usually offered whichever UI is least useful for my current configuration
It's finicky on occasion, but when you are used to it, it's surprisingly intuitive practical! It wasn't super popular though, and I imagine it could be annoying to users who didn't want it. It appears they only did it for a few models, ending in the S5.
That phone was pretty interesting, sensor-wise. I kind of miss using it, and I wonder if it would be practical nowadays.
[1] Air View: https://www.samsung.com/hk_en/support/mobile-devices/what-is...
[2] Air Gesture: https://www.samsung.com/hk_en/support/mobile-devices/what-is...
The problem is that long-tap gets used for a lot of other things on Android (extended selection, particularly). The user experience is pretty unhappy if you use both conventions. And, in practice, long-tap tooltips are so rarely provided on Android apps that I doubt that ordinary users would expect them at all.
As far as I know, tap-and-hold (as distinguished from long-tap) isn't a conventional gesture on Android.
It's an augmentation that can be used on desktops though. I agree that it shouldn't be necessary but, but it can help. Some apps aren't meant for mobile either.
At least sliders generally have right for on, as opposed to pure text toggle buttons which are just awful.
Checkbooks are quite self explanitory.