I think they CAN be good. As others have written, it depends on the application.
I recently did sound for a show. I brought some great dynamic mics (MD 441, 421, Beyer M88, etc.). The singer tried a couple and then opted to use his Beta 87. And I have to admit it sounded better for his voice; clearer and with response curve well-suited to him.
BUT - it was an outdoor gig, meaning less feedback problems, and the monitors were at the sides, where they ought to be with hypercardioids.
Plus, he plays piano, so his head is always providing a baffle from the drums behind him.