Tasteful - yes it sounds prudish, but you are right. There's a difference between erotica - because sex isn't wrong or shameful or something to hide - and full blown porn - because porn is born in the environment OF repression. Erotica is... well, a celebration of sex. An acceptance. An appreciation.

Porn is a desperate outlet for those trapped in the 'sex is wrong' mindset or society. Porn is wrapped in stifling robes of repression and shame - the dirty little secret, the mags hidden under the bed.

How to put it? Porn hides under the mattress. Erotica sits on the bookshelf.

(I'm not sure on the visual vs writing, since I'm a guy but see the appeal of both).