Arpeggiators are commonly used in live performance, and for easy automatic creation of arpeggios. Such programs allow you to create arpeggios following the same pattern for different chords, faster than manual creation. They are most often used in conjunction with a synthesizer.
The program reviewed in the article is not entirely suited for live performance, but I am interested in the other two programs he plans to review.
Perhaps they would not be useful for you, but they are an interesting music creation tool.