You can waste time without a phone and you can do programming fairly productively on a phone (I lived without a laptop for 6 months, did everything in Termux!).

You can waste time without a phone and you can do programming fairly productively on a phone (I lived without a laptop for 6 months, did everything in Termux!). But there's a right tool for every job, and the phone is designed to steal your soul (attention), designed to encourage mindless consumption, and interrupt you as often as possible. This is part of a bigger principle I've noticed where I can rely on sheer willpower, or I can simply make a small change to my environment (e.g. move the phone to another room) and that's a much more efficient way to achieve the same result. It's partly about reducing the Temptation, and partly about setting a strong intention / setting a strong message to yourself. If you're serious about getting some real work done, then why are you even looking at your phone? Eventually you can get to the point where wasting time in any way starts to feel gross and you catch yourself more and more, but for most people it takes a bit of recalibration to get there.