Datasheet specifying less than 0.1 uF decoupling capacitors
A 0.01uF cap will have a higher self-resonant frequency than a 0.1uf capacitor. It is probably to keep a low impedance on the supply over a wider range of frequencies.
Notice that there is also a 0.1uF capacitor directly between the rails. I have had to use that on one occasion because of difficulty in decoupling the supply rails the usual way. (That was also with a National Semi opamp).
There are various ideas about the &quot;best&quot; way to arrange decoupling and some use multiple capacitors of different values to achieve the goal of a low impedance supply over a wide range of frequencies. Usually I find that a PCB layout with adjacent buried power and ground planes can do very well with the normal approach.