Is it a good idea to start a career in Martial Arts acting?

It depends on your ability and your connections. If your Chinese is good, you might be able to get into movies in Hong Kong or China with bit parts. The odds of turning it into a career such as Jackie Chan or Jean Claude Van Damme are slim, but it is obviously possible! And if you can start off with some bit parts in TV and movies as an extra with some martial arts skills tht is a starting point.