They can list whatever they want but actual scientific study after study shows no relation between hydration or electrolytes and cramping. One study I read had participants get ridiculously dehydrated. Result? No additional cramping.

From another study: the "electrolyte depletion" and "dehydration" hypotheses do not offer plausible... mechanisms... that could adequately explain the presentation of [cramping].

You'd think if what Mayo Clinic said was true it would be easy to find lots of studies to back it up.