The biggest departure from reality in the Utah cold fusion experiment was that it supposedly didn't emit large amounts of radiation, which would make it a practicable portable power supply that could, for example, easily power vehicles. In the end, that was one of the strongest clues that the experiment was not creating fusion.

If someone does get cold fusion working, it would be just as difficult to shield and gather power from as confinment fusion experiments, but several of them still have promise as potential commercially viable power sources, so if cold fusion could potentially compete in the same ballpark, it would still be remarkable, despite not being the miracle power source initiall envisioned.