I wish they used it more as well,i remember watching my brother play a DS9 video game where if you attack a Vorta they will use it on you,it was so cool.
Yeah, in "The Fallen" you can fight more or less evenly with a telekinetic Vorta by wielding a Breen-style shock-stick (amazing what you can find in a FPS!). But it does hurt.
Perhaps in the "real" Trek universe, those telepathic bolts were a prominent characteristic of the Kurillian species that Eris claimed to be a member of, and Eris was given this ability in case our heroes had already heard rumors about this species and would see a discrepancy if Eris lacked the ability?
In this theory, the ability would serve no practical use in other contexts, and would not be introduced to all Vorta. Either it was a harmless light show (and both Sisko's stunning and the breaking of the forcefield barrier were faked with technology), or it was a semi-decent stunning tool but not really worth the hassle (much like in "The Fallen").