Lifting works faster. Trying to change your posture by noticing and correcting it is just brutally difficult. You need to mindfully check in multiple times an hour. Lifting you only need to attend to your posture while you’re doing it and your posture will improve without conscious effort as your tendons and sinews stretch and you get more muscle. Running or dancing will do the same thing but the returns on each hour of work are going to be lower than for lifting weights.