Quality of a product (and its properties) must be measurable, otherwise it is not quality. If it is measurable, it has to have an objective measure. Completely subjective things (like film) do not have an objective measure. There is no objective measure for properties such as story, acting, dialogue, music, sound, etc.
Then what term other than “quality” would you use for measuring how good you think something is?
And you don’t measure anything. You simply think how good something is.
There should be a term that pertains specifically to measuring enjoyment. “Quality” works for me because how good I think something is and quality are the same thing when talking about what’s going on in someone’s mind.