Because the two valve types are different they require two different types of head on a pump or as is often the case an interchangeable head.
Bicycle pump valve types.
Kitbest bike pump portable bicycle floor pump with glueless puncture kit mountain road bike tire pump mini bicycle air pump compatible with presta schrader valve and sports ball by kitbest 12 99 12.
This type of hand pump features a separate tube which connects the bike pump to the tire valve.
Compared to schrader valves presta valves are ideally suited to bike wheels.
An integral bike pump has a hole covered with a rubber washer which fits into a bike tire valve.
There is minimal chance of air leaks making it more.
It is cheap but inefficient due to higher risk of air leaks through multiple joints.