I see it becoming more and more popular on porn sites.  

...if you look at it from the Quentin Tarantino perspective--I know, but stay with me...for that one Kill Bill movie when asked what made him do the animated scene about Oren Ishii's childhood, he said that by doing it in animation, he could accentuate various elements such as blood, pain, facial expressions, etc, that he couldn't replicate in real life.  I think in porn, it allows the creator to accentuate ass, tits, cock size, proportions, orgasms, fantasy, etc to a point that is unreal.  The few (3-4) hen tai scenes I've seen had screen captures that displayed something unattainable under most circumstances in real life porn.  Whether it's the woman's proportions or the ability for her to down a massively sized cock or whatever.

I'm going to assume its based off a need for control. In hentai/anime, a persona can create their ideal image of a women and what she's doing. In these cartoons 99% of the time these girls are submissive and either go along with what's happening or are forced. Either one can be a turn on for the right person watching or creating. Plus, the girls are put in situations that aren't normal: 10 inch monster cocks being stuffed in a girl, huge (DDD/HHH/LL?) breasts and size 20 waists, etc.  

What you described is what happens in LIVE-ACTION porn in Japan!
 

Hentai anime allows for greater narrative depth and character interaction than is finacially or legally feasible in live action hardcore pornography.  On the occasions when a hentai manga (comic) is adapted into both anime and live-action projects (such as Weather Report Girl), the anime is always hardcore and the movie is always softcore (allowing it initial theatrical release and eventual television broadcast).

You were a normal OP, I'd point out something the whole Japanese sex culture. But it's you.  

I believe it has to do with censorship laws in Japan. Like how most Japanese porn has the penetration blurred. 2 actual people having sex, it has to be blurred. Cartoon people or people fucking robots or squids or robot squids cool.

Who the fk wants to be a "normal" OP? Not me. Not now. Not on a fk board. lol

Be honest. You provide the voice overs in the U.S. for this shit, don't you?

You shouldn't offer an opinion about which you know absolutely nothing.  
ALL images depicting reproductive organs must be censored in accordance with Japanese law -- INCLUDING HAND-DRAWN (cartoon/comic) IMAGES!  Interestingly, the anus is not a reproductive organ, so depictions of anal penetration by anything other than a penis is uncensored.

English-dubbing is an unuseful and idiotic practice.  
It is just about the only job in the entertainment industry I would never consider taking.