The point is that if the Iokans were able to find and use dreamstone then the post Fall Zealians would have been able to also. Presumeabley Dreamstone would be extremely uselful in its raw form, and comparable to diamonds in that they are impractical sometimes, but can be put to good use.
Even if it wasnt able to be used, the allure of it would attract people to use it as jewelry or a status symbol or, hearkening back to the roots of humanity, as a form of currency. From what we see, dreamstone is not ugly.