Doug,
The piano
is chromatic. WBWBWWBWBWBWW(key color= 1/2 steps)
A pianist can play a C chord in consistantly every octave with the
same fingering. If you play a C chord on guitar at the 1st, 3rd, 5th, 8th and 10th frets you have to use five different fingerings and your voicings won't be consistant. Even if you use only triads your fingerings will change.
If you want to finger an F barre and
slide up to A at the fifth fret you can use the same shape, a pianist would have to change fingerings to do the same.
Each instrument has its trade offs. But both are chromatic.
Regards,
Monk