Hot Fuzz wasn't so much double dipping though. It was a bare bones release for the curious and a spendy three disc affair for the lovers. We knew to avoid that bare bones release because we were gonna get that three disc set soon enough. I don't consider it double dipping if they tell you a better version is coming out before the bare bones is released.
Now that I actually look into it they've already released a bunch of different versions of Grindhouse. The single disc set of each, the 2-disc set of each, the steel book 2-disc of each, a 3-disc steel set of both movies together, a six-disc set of both the movies, and I believe there's a box set that has the 2-disc sets of each packaged together. Don't know why anybody could possibly need another version.
Putting out a set with both of them on one disc sounds absolutely absurd to me at this point. How hard is it to watch a movie, take it out and put in another movie? Especially if they're not the extended versions. If they had released the theatrical versions on the same disc first I could maybe justify it. Just feels like a cash grab at this point.