dunno about impaction, I think that risk is with mealworms, not supers. As long as your cham is well hydrated it shouldnt be an issue. Superworms are actually fine as a staple as long as theyre gutloaded, and as long as you offer a variety of other feeders so its not 100% supers. Ideally crickets or roaches should be a staple because they have a higher stomach capacity and therefore a higher gutload capacity, but plenty of people here use superworms instead
I think the general assumption is that because they're relatively high in chiton they shouldnt be used, but I think a lot of the confusion comes from mislabeling giant mealworms (T. molitor) as superworms (Z. morio), or vice versa
I'm just going to chime in and say ideally you shouldn't have a "staple". I know, I know, easier said than done and I will admit to using crickets as a fallback and my chams probably get a higher percentage of those than any other feeder. That being said, I did say "ideally" Try to use as many different types of feeders as possible: crickets, roaches, superworms, silkworms, hornworms, phoenix worms, etc.
I also feel that crickets and roaches are easier to gutload, but superworms can definitely be gutloaded. However, I do believe they are a bit high in fat so perhaps not the best choice as a "staple". Try reading over some of the info here: https://www.chameleonforums.com/blogs/sandrachameleon/75-feeder-nutrition-gutloading.html and follow some of the links. There are a ton of choices out there and the best thing you can do besides good gutloading of your feeders, is variety.
As previously stated there is not much risk of impaction from superworms. They are, however, not the most healthy feeder as they are high in fat content and have small stomachs (decreases efficacy of gutloading). They also are know to cause "addiction" in chams where they will refuse all other food besides superworms (this has happened to me).
Superworms should at most make up 20% of their diet but are better used as treats.
I stopped using superworms for a long time after I had to pull a superworm out of my Jacksions vent. It was just the outside skin but it worried me that he couldn't get it out, and it was the entire superworm. I did take pictures because it was crazy.
But now that I am having some difficulties with my silks and have a little less variety for my guys (just roaches, crickets, isopods and horn worms right now), I have started supers again........but not for my jackson. I still don't want to give him anymore so they are only for the panther and my beardie. I think they are safe as an addition and should not take up more than about 20% of their diet.