Why water towers?

This is something I’ve pondered for a while. Why are water towers so popular when it seems to be less efficient than having a ground-level or underground tank or reservoir? I mean, you have to build the thing really tall, then you have to pump water up into it, and then, I don’t know if this ever happens, but it seems to me you’d have the worry of the thing falling over.

This seems inefficient to me because it’s way easier to dig a big hole, stick a tank in there, and then fill it with water. Is there something I’m missing? Water towers seem to be pretty popular.