I sincerely doubt that. The Jewel Sword does draw on extradimensional sources - but only tiny drips of energy, from all of the user's "nearby" dimensional analogues. No harm there.
As I said, I'd expect the TSAB would try to restrict the Jewel Sword Zelretch, because it has a potentially high amount of power to draw from. They do the same thing with the L'arc-en-Ciel, though that's an extreme case. The Jewel Sword is basically just a weapon, and it performs as advertised, and no further. That makes it relatively safe to use, within reason.
The Jewel Seeds aren't the same. They are inherently wish-granting artifacts, but their problem is that they're too sensitive. The kitten wanted to be bigger, so it grew to several stories in height. The guy and the girl wanted to be together, so a giant tree grew and encapsulated them together. It's pretty simple, yet dangerous, just like anything that has wish-granting ability.