The animations are certainly resource intensive to create, but they're also an important part of all DPC's Patreon support. They're what pay the bills, which makes them effectively cheaper than free!
I do think the game could stand on its own merits without the hardcore sex, purely on the strength its visuals, music and characters. It would still be a raunchy sex farce, just more of an R rated one. But I'm not sure there was a ready audience that would have financed it that way, at least not enough to reach critical mass and get the game started.
So the sex scenes are a vital part of the game and fortunately they've generally been high quality. I do think Episode 5 went a little overboard. The scenes themselves worked well, but the episode not only had a very high ratio of sex-to-story, it also insisted on cramming almost all the sex scenes into the span of a single (incomplete!) party.
I'm hoping we can keep the high quality, plot relevant scenes going forward without it feeling quite as artificial as in Episode 5. Personally I'd be fine with fewer total sex scenes if they all felt well integrated into an advancing story, but I may be in the minority on that.