I believe, as in another recent thread, the issue here is Indian airports (the other thread was BOM related) like paper.
In the other thread I commented that I've heard/experienced needing a paper print out of my proof of e-ticket to get into the airport and heard that a BP on my phone would not be sufficient. Some people said that was incorrect, others said it was. Who knows.
If I travel around anywhere outside of US/Canada/UK ... I take paper copies. And this includes things like eTA/ESTA proofs - anything electronic. I've even had customs (US) demand to see paper copies of hotel bookings before, and a friend had the same thing in a different trip.
And while I too always try to get a paper BP from AC; in one case the agent said it was impossibru. Fortunately that wasn't in India.