In any protest or political movement, oratory is extremely important. If you're not a good speaker and can't communicate effectively in the language people understand, it's difficult for them to connect with you.
The entire Anna movement was kept alive and driven largely by Kejriwal oratory. Without Arvind Kejriwal, the Anna movement would have been a flop. There were many capable people involved, but most people would specifically wait to hear Kejriwal and Kumar Vishwas speak.
Kejriwal's oratory was unmatched.
Voh toh jhatu janta ke liye apna level down kara liya to connect with the masses, but otherwise even his English speeches especially the technical, policy oriented, and business related ones were exceptionally impressive.