Shelby,
A lot of technique differences come from different string tensions — smaller harps, be they south american, folk, or older single-action harps are going to require less force for the string to vibrate fully. Modern instruments require more force, and thus you use your entire digit, with hand, wrist, forearm, bicep as support.
Lighter tension does mean certain repeated passages or oscillations are much easier… which is why folk music has awesome ornamentation 🙂