Our project is partly software, and partly 3d models and images. To me, the language of the MIT license, which specifically refers to software, doesn't really seem applicable to the parts that aren't software. For that matter, it seems onerous to talk about including the copyright notice for people who just want to make use of the 3d models and images.
This answer suggests that placing a dual license of MIT and CC-BY on everything is a good solution. Is it really?
GitHub has a standard approach to displaying licenses, and I want to make use of it so the license is easy to find. So it would be really nice to just put both licenses on everything, otherwise I have to split things up by file type or folder, and it gets messy and could make it more troublesome to include the proper license or credit notice in downstream works.