re: Why is resolution a measure of quality for smartphone screens, but not cameras?

Sounds more like arguing semantics.

Megapixels does not equal quality. It equals how large an image can be at a fixed DPI, or how many dots can be crammed in a fixed size. But at the same time, we don't want a 400x600 low-resolution picture if we're trying to print an 8x10 photo. But also at the same time, we don't want a noisy photo from a shitty phone camera sensor, which is totally independent of resolution.

I'm pretty sure we are all saying the same thing.