I understand these, but there are instances where these special "power only" and "data only" cables come into play. They are not too common and are usually specific use cases.
For example, on unmodified Ender 3 Pro 3D printers, it's ideal to use "data only" cables when connecting the printer to a Raspberry Pi or computer, because the stepper motors can backfeed unregulated voltages into the USB power lines, and that's not good.
And an example of "power only" cables is when you want to use a public USB port to charge something, without the risk of compromising your data or opening up your device to software attacks. Like charging your phone on a thinclient computer at work, for example.
But yeah, I 100% agree with you on the stance of buying quality cables, it makes all the difference in the world. I have thrown away all my shitty/shady/slow-performing chinese cables, and have invested in quality cables by Anker that can handle up to 100watt PD charging. And for my few-and-between Micro USB needs, I use the official Nintendo-branded cables that came with my NES Mini and SNES Mini consoles. They are substantially high quality for Micro USB, and have nice fat heads on them for a secure connection. They click in firmly, as they always should.
Samsung, Nintendo, Anker, and UGREEN all make quality cables you can trust and depend on.