True there are a limited number of movies showed in IMAX venues and then released for the home market in their 1.89 or 1.77 AR. The number is made larger if you include the 3D home version if that is your thing. The vast majority of these movies also could have been viewed in commercial 2.4 scope venues as cropped and there is a legitimate case to be made for showing them scope safe at home if you have a 2.4 scope setup in your home most likely it would be front projection.
The IMAX height version is normally considered the directors choice of presentation if they provided it that way to the home market. Even without publicly saying so it can be logically implied they made a movie in IMAX and then had it put on disc as IMAX that they most likely prefer the IMAX framing and if it has changing ARs it is that they wanted it to have changing ARs.
The number of these movies should only be important to the degree we as viewers want to see them. If you are a big fan of modern action, super hero movies and also a fan of 3D versions of those movies it is pretty logical you wouldn’t want to crop them.
There is nothing about an IMAX sized screen that takes away from a scope movie in any way. The scope movie fits in there just perfectly given you have tall enough ceilings to accommodate the IMAX movie, and if masking is important to you then you provide upper and lower masking. Removing the lower only masking solves a big problem when streaming a scope movie with subtitles down there, as there is a place to show them.
These movies started coming out and provided a problem for people that had established scope theaters at home. The simple solution was to hate them, say the extra content wasn’t important and then crop them. There really isn’t anything wrong with that approach actually. It was the simplest solution to a difficult problem.
But what about the blank slate people planning a home theater? IMAX movies are not a problem they haven’t started yet and they can do anything they want. Why would they not want to include these abilities if they want to? The projector they will buy is 16:9 and I don’t hear a lot of clamor demanding 2.4 projectors. The A-lens solution in essences converting a 16:9 projector into a 2.4 projector is an expensive one and most are not taking.
IMAX sizing a screen is just an option and not for everyone, but it really isn’t a big deal to do if building a new home theater and if done properly will have zero negative effect on any non IMAX movie scope included.
It boils down to immersion and some say go as tall as you would ever want and then go wide as scope requires. For me going as tall as I would ever want is what IMAX is and there is a relationship to scope based on that, and scope would be both too tall and too wide if I did that.
There is no other way to explain it except to find a blank white wall and test immersion and watch IMAX and scope and see what relationship works for you. Turn on the masking feature and watch any of the IMAX AR changing movies with and without it and see what you think.