By grooming you can also spot problems that you may not ordinarily notice such as lumps or cuts. Plus grooming gives you and your cat a deeper bond as they will like all the extra attention they are getting.
For cats that have never been groomed or dislike grooming, introduce it to them slowly by calling them gently and introducing them to treats (they will like you for this) before you brush them. Brush in the direction of the coat - this is much more gentle on them. Keep the brush in different locations - generally close to where you sit and may groom the cat from. If the cat realises your going to the cupboard with the brush in, it may make them run for the door.