I was just thinking about this - I think I like erotica better than porno movies because in erotica, my brain can fill in the gaps, or can imagine the things I like in the things that aren't said.
I think good erotica will just use generic terms like "In her leather boots, she was a tall, very attractive, commanding woman, wearing a big strap on" and that's it. There might be one or two descriptors for her leather corset or something... but not much else.
Which leaves lots of wiggle room in the reader's brain. My brain can fill in the gaps with whatever physical descriptions turns me on at the time for the story. My brain automatically says "ooooh... she's a petite brunette with a very cute face, pretty smile, and really, really large breasts." Or "Oh she's a 6'2" smokin' hot red head with a nice curvy ass and neatly trimmed ginger pubes."
But in porno movies, you get what you get. Not a lot of room for the viewer's visual embellishments.
Also, I think erotica allows the readers mind to embellish the scenario - giant mansions on a tropical island with multitudes of naked slaves... or whatever would be glorious to look at, but well outside of any sort of realistic filming budget.
I never quite considered it from that point of view but I agree with both your points.
The human imagination can paint quite a picture.
