There's an element of multitasking that is (while not exclusively) inherent to piano definitely is an important focus.
For instance, I play a lot of stride and blues piano. One of the hallmarks of those styles is having a rock-solid left hand that can maintain ornate but very consistent patterns. Once that’s locked in, your right hand is pretty much free to do whatever it wants. You'll find that your right hand can literally be almost totally independent.
It can sing out the melody, feed yourself grapes, or turn the pages of a book while your left hand just keeps on going - honestly fatigue is the biggest factor particlarly at higher tempos.
OTOH, musical multitasking where the left and right hands (or different parts of the body) are genuinely playing new, independent lines is tremendously more difficult.
Mad respect for Johann Sebastian Bach, who by all accounts could extemporize contrapuntal music essentially inventing fresh, independent patterns in both hands at the same time. I know that’s not multiple instruments in the literal sense, but in effect it kind of is, especially when you factor in the foot pedals of an organ.