I was playing a game on my phone. The game was completely lost, but I had a strategy. Probably wouldn't have worked, but I wanted to play on.
I got a message on my phone and went to answer it. It took under 30 seconds and I had 10 minutes left on my clock. I saw the game abandoned message and went to see why.
I repeat, 15 seconds is too short a time even if the position is lost.