Hartley needed this bowling innings, so I'm pleased for him.
I always like the thought of a tall left-arm spinner, who bowls it quickly, in India (and Hartley fills that brief). It doesn't matter if they naturally can't turn the ball very much, because Indian pitches will invariably do that work for them. I don't think it's a coincidence that our one test series victory in India in recent memory is when we were able to play Monty (another tall quick left arm spinner) alongside Swann.
But Hartley did suffer quite badly in the first innings, and if this second innings had gone against him too, his place might have been in question (and whilst I love having three spinners in India, I do think four is unnecessary).
The fact that he's handy with the bat (by lower order standards) is helpful.