Never say never or no to anything. It is all music. You will get something to learn from other styles of music. By incorporating many different things to your playing, you develop you own style of playing which will be only yours. Or else live your life playing other people’s songs, all your life! There is more to playing guitar than the ability to play the intro of Nothing else Matter or Chords of Hotel California or the Riff of Smoke on the Water!!
In India, we have to be versatile and fluent in many styles of playing. Especially if one wants to make a decent living out of it. A decent living only from playing guitar.
Having a day job in an IT company and playing on weekends, is a different thing.
If it is a hobby and not looking to make any steady income out of your hobby, you stick to one style; if you wish.The fact is, if we are comfortable playing many styles, we get more gigs. People would call us to play for them.
For example, I have seen one of the most respected guitarists in India, playing in Rock bands, normal south Indian orchestra playing film songs, playing in a Kannada folk singers band, jamming with Eshaan Noorani in a blues band……etc.
I have seen many bands come and disappear from the scene in the last 30 years in India. But this particular guitarist is always in demand.
So as a professional musician, one cannot say “I play only Heavy Metal” unless and until one has a steady job in a Heavy Metal Band.