The reason I'd rather not have it is the price tag. I was glad with Into Darkness that there was a 2D steelbook option, and a 3D one. I obviously chose 2D, and those that chose 3D got the extra disc they wanted and alternate artwork. I wish they'd done a similar thing with Pacific Rim too.
It's okay though, I'm starting to slow down buying new release steelbooks. I've decided to limit myself to films I really want in my collection (Halloween, Seven Samurai, Nausicaä) rather than just always opting for it out of habit just because it's there. For instance I'm thinking of going for Nosferatu and Only God Forgives on amaray, but I may get Alpha Papa and Elysium as steelbooks.
I have a 3D TV, but I don't have the glasses. I have a feeling this will be good for 3D - probably one of the best, as along with TRON: Legacy and Star Trek Into Darkness it's the best 3D I've seen so far at the cinema - but I couldn't take it at home. Maybe it's just the people I live with combined with the setup and the fact I don't have the glasses. We have a few films in 3D (Avatar and Titanic came with the Blu-Ray player, and we also have Prometheus), but I've never felt the urge to go out and buy the glasses seeing as most 3D gives me a headache (both Pixar films I've seen in 3D gave me a headache, despite enjoying the film). Personal preference I guess.
But my original point was there's no need for 3 editions in 3D and only one in 2D. Would've been nicer to see a special edition (not necessarily steelbook) 2D version of the film for those that prefer things flat.