Some beardies will eat the "canned crickets" that some pet stores sell, some won't.
Either way, the canned ones are quite a bit more expensive than live crickets, and less nutritious
(since you can't gutload them and because of the canning/preservation process).
Crickets are, in turn, quite a bit less nutritious than some of the other options (Phoenix Worms, Dubias, etc)
but are easier to get and cheaper (unless you start up your own colony).
Those beardie pellet foods are OK as a supplemental diet, but you shouldn't really use them as your only food,
(assuming you can get your beardie to eat them at all -- neither of mine will touch the stuff).
Yes the label says those pellets are "complete" nutrition, but you still need to give good gutloaded insects and
fresh salads/veggies, in my opinion.