After just completing a list of 3D Apps for this site, I just came to a pair of realizations. First off, the demo is all but a requirement these days. Second, and this is the point most missed it seems, but these days integration with other suites is perhaps the most important feature. Therefore, if your application’s demo doesn’t support saving, importing and exporting, testing it’s ability to slot into your pipeline is almost impossible.
To use an example, if I want to test how well Cheetah3D works with Unity, I simply cannot. Given the horrifying number of problems and artifacts that occur when moving from various programs to programs, this is extremely important information as part of my evaluation process.