LF: Again, those are of my own humble opinion. Maybe yes maybe no. Another MAJOR consideration is of another’s view of this individual. In a shul, together in a minyan. It also has to be considered. It’s a TERRIBLE chilul HaShem in my view. Hey look there, there’s a guy playing on his toy during Davening. Maybe I too don’t have to exert myself so much…
I disagree. You wouldn’t say the same about someone using a Siddur. “Oh look, he’s reading a book instead of Davening.” People know that phones have Siddur apps. People know that phones have airplane modes. Whenever I see someone on a phone in Shul, I automatically assume he’s Davening from it. What else would he be doing? Now, the person with a phone in his pocket who runs out when it starts buzzing… (Well, hopefully his wife is in labor.)