Yes, if you're a water gardener who wants the sight and sound of moving water.

Yes, if you're a fish keeper (and especially a Koi keeper) who needs to feed the filters, circulate pond water and aerate it.

Pumps are simply motors that drive impellers to draw in water and push it out again. Apart from a few solar-powered pumps, most run on mains electricity at 230 volts, with some stepped down to a lower voltage. Solar power mean no worries about cables or electricity, and can be used for pond fountains and air pumps, and self-contained water features.