Along with a piano stool or bench, a metronome is one of the classic accessories you need to play the piano. If you want to learn to play rhythmically and accurately, you should always practice with a metronome. Often, misinterpretations of notation become apparent only when working through a piece with metronome accompaniment.
You can also use a metronome to systematically practice a newly learned piece. Start with a slower tempo and increase it a little each time you can play the critical passages cleanly and fluently. In general, practicing piano with a metronome will train your sense of rhythm.
It also gives you a better sense of timing when you play the piano – even when you play the piece you practiced without a metronome. In addition, you can use a metronome silently during a performance, whether you are playing solo on stage or live in concert. However, choosing the right metronome can be challenging, as there are many different approaches and technical possibilities.