Power supply capacitors in an amplifier circuit
According to the PA107 datasheet, \$V_{SP}\$  is the high voltage power supply to the output stage of the amplifier.
The other power supply pins are for the low voltage parts of the IC.
Since the voltage levels in the two parts of the circuit can be very different, they are powered by separate pins.   Low voltage for most of the amplifier circuit, high voltage and high current for the output part.
\$V_{SP}\$ supplies large currents at a high voltage to the output transistors.  You need large capacitors to supply current for fast signals. You need a 1uF to handle the faster parts and then 10uF per expected ampere of output current to handle heftier surges.
Small capacitors react faster to sudden changes while larger capacitors can supply more current for a longer time.
You need both - you shouldn't say &quot;I need two amperes of output current so I'll use a 21uF capacitor.&quot;  You should use a 20uF capacitor and a 1 uF capacitor.