If your wheel isn't round, isn't not really a wheel. It's a false wheel, its not a true wheel. Wheels need to be truly round to roll easily. If you're trying to pedal a bike whose wheels need adjusting, you're going to waste a lot of energy to compensate.
If you look a bit more in depth about this topic, you'll find that many people will dismount their wheels and put them on a truing stand.
Nuts to that.
Unless you're racing your bike, you can get by with this home truing method.