You're absolutely right, but it all comes down to the project requirements and both are valid methods.
Can more than one pump be used?
Does it have to be a reversible pump?
These are question OP can help us understand.
Edit: The valve setup can also use a couple y-connectors to reduce the connection to a single tube to each bowl and if that tube is at the bottom of the bowl then it can have a very impressive filling and draining effect while completely hiding the tubes.
