Growing up in India, we always used whole chicken, including skin, bones and dark and white meat. It is only a recent phenomenon that we get to see a set of breasts / thighs is high-end superstores in India, perhaps only in bigger cities. Purists may want you to use the whole chicken, but it is not very convenient.
Although I prefer using chicken bone-in, since it gives more flavor to the dish, I understand that most of us prefer otherwise, since it can be messy. And I agree. However, using chicken thighs for a curry dish is very important. Dark meat of chicken comes from areas that the chicken must have exercised during its life-time and therefore has better flavor. It cooks well for a long time in a curry dish, much better than chicken breasts / tenders.
I would disagree that chicken breasts are much leaner than chicken thighs, and if one is concerned, one may always trim-off the excess fat. Using chicken thighs (boneless or bone-in) is much cheaper than chicken breasts. This is yet another reason for using red meat, the price different is substantial.