Yes. This is may actually be a smart move by him.

He knows that he is going to have to give out lots of the regional caste-based votes to the regional parties, in all the pre-poll tie-ups that are bound to happen in 2019.

So, what is that single vote-bank which he can claim for his own and give him a pan-India image?

It is the Muslims. So, that is what he is doing. He knows that with those 15% votes in his pocket, plus his regional tie-ups he has a real chance. There is no way the BJP can consolidate more then 35-40% percent of the Hindu vote, cause Hindus are not a single vote-bank but multiple caste-based vote-banks.

He is doing right by going after the biggest votebank in the world. 12 crores voters (assuming 15% of ~80 crore voters). That is bigger than the voters in whole of Pakistan!!