Tony Vargas
Legend
Nod. If a setting intentionally juxtaposes the conventions of science-fiction and fantasy, and chooses not to resolve as one or the other, it can place scientifically-correct technologies and psuedo-scientifically hand-waved psionics along with scientifically-insupportable fantasy conventions and magic. You could have the Enterprise visit Discworld, and the natives would use magic, while Mr. Spock would remain psionic.… Unless both exist on the same story. Then clarifying the situation seems a necessity.
But, doing so tends towards the incoherent. About the only genre it makes sense in is comic-book superheroes.
To fit the sci-fi genre, yeah. That's the thing, psionics in a fantasy setting is, OT1H, nonsense, since psionics is just magic with the fantasy serial numbers filed off, OTOH, it's genre-blending, like Conan with a raygun, and you can do it if you really want to, OTOOH, 'psionics' could just be a different form/style of magic in such a setting, just a 'casting spells' could be a form/style of psionics (or a 'sufficiently advanced technology') in a science-fiction setting.Yes, I do get that psionics is the sci-fi substitute for magic, but they are different in feel, description and definition
In the context of D&D, I think 3.5 made the best call in leaving it to the DM to declare psionics is magic or psionics is different.