I think I would have failed in any other exam, especially State PSC examinations.
I don’t know about other states but there is a predominance given to factual questions in Kerala State PSC Exam. Your UPSC CSE preparation needs more of a conceptual understanding. Therefore a UPSC question would ask you about the Indian Ocean Dipole, while a State PSC question would ask you about the name of that tropical cyclone that hit the coast last year. You might have read about it in the papers, but unless the damages were extensive there is a good chance you would have forgotten it. Thus to compete in the State PSC exams is a whole different ball game.
The other option is the bank exam. UPSC prelims paper II is of a qualitfying nature and therefore you don’t have to be a quant guru to pass it. Whereas bank examination requires you to be a boss in Quant questions, logical reasoning and English language. I would not have stood a chance with those aspirants with my UPSC CSE skills.
Therefore, in my case, I would say I would have failed in any other exam with the preparation level of UPSC CSE. That said, I am pretty confident that I would have made it in any of these exams, if I really wanted to pass them ( I never did)