One question.
Have you ever used a shark bite?
. There is absolutely no rigidity in it at all. You can throw all the engineer stuff at me you want, but if you have ever used a shark bite you will know why I have concerns. These fittings look exactly like a shark bite fitting. They may have made some changes and that is what I'm trying to figure out and see if someone has installed one. On straight runs with proper supports its probably fine. I'm concerned about the mechanical rooms and industrial settings where conduit doesn't only run in a straight line.
If the conduit is secured properly, they will likely work just fine.