Comment by simondotau

My (deeply uninformed) guess is that it probably wasn't absolutely necessary, but would be one among a hundred tiny details which improves resilience. There was space for it. And it has a $0.00 unit cost. It'd be more surprising if they didn't do it.

For Apple, perhaps the most economically exposed to customer problems of any major tech company, and has enough scar tissue from past failures, it's not surprising that their products tend to feature first class electrical engineering. Their DC chargers are widely regarded as among the best in the industry.