Assuming a MetaTrader4 trading platform, a PC is-non optional for most technical traders. The mobile MT4, while very good, cannot upload custom indicators, so unless you are content with the default indicators, you won’t be able to apply your trading system on the mobile platform.
That said, the default indicators are very good, and I’ve traded profitably using them. But most of us have to go through a phase of thinking that ‘better’ indicators will result in better trades, when the problem is actually us.
Now that I’m trading price action, everything goes through my tablet. Like most people, though, I find the phone very useful for checking in on open positions.