yah- it's bull for bearded dragons as well.
It's an excellent example of speculation started on the internet by some well meaning but ignorant individual getting passed around as truth and spreading as fact, rather than speculation.
Supers can't chew their way out of stomach acid. They drown in a bit of water in a few seconds.
This bit of folk lore was more popularly passed along 10 years ago, but even now occasionally someone will pop up who swears one ate it's way out of their lizard, or a friend's lizard. Absolutely laughably false. What *might* happen is a stray superworm loose in the cage might be hungry and eat a lizard that died and started to smell a little, and then the owner might find a super eating around in the lizard and think it chewed out. They will not eat a live lizard...
for whatever it is worth- I've fed them for many years (15 or more?) to hundreds (couple thousand?) of lizards and never had a problem. Bert Langerwerf (the guy who "invented" the superworm in the reptile hobby) fed them for decades to many thousands of lizards (tens of thousands) and never had a problem either...
For whatever else it is worth- I feed my lizards mealworms as well as superworms- both are good for variety. Supers are better alone nutritionally than mealworms, but you should not use any one insect alone for the best results with your lizard anyway...