At the moment, yes. I usually mess around in a game like Don't Touch The Spikes while listening to music or while waiting for an event to happen, someone to arrive, an ad break to end, e.t.c. I used to play a lot of other mobile games more for the fun factor or for the competitive side, such as Clash Royale and Asphalt 8. But I got a bit too carried away and ended up nearly frying my brand new iPhone. There's no harm in playing mobile games seriously or competitively, but it gets a bit boring, especially if you don't have any peripherals.
Consoles and PC's do ultimately offer a better catalogue of games and peripherals to play with, as well as a much, much bigger screen. That's not to say you can't make yourself a nice mobile gaming rig though. Pair an iPad Pro with a keyboard and one of those aftermarket controllers, and you have yourself a decent, albeit expensive mobile gaming station.