I know that playing scales is seen as boring at best or useless at worst, but learning to play scales are actually beneficial in many ways.
Learning to play scales is actually a really straightforward way of keeping your hands nimble because you are playing one note at a time and the notes are close together (unless you are playing arpeggios or broken chords). Playing scales are an excellent warm up or a way to get your fingers moving again after you have had a break from playing the piano.
Playing scales is not only useful for keeping your hands and fingers moving, but playing scales is a great way of really understanding what a particular key sounds and feels like to play. By playing scales you fully learn what sounds make up a particular key far better than learning about it from a book or website. Playing the scale really internalizes the key.
What is not well known about learning to play scales is that it teaches you how to play fast. This might not seem like a thing and most people would presume that you don’t need to learn how to play fast, it is something that you just do. Actually, in order to play fast, or at least faster than you have before requires you to not only move your fingers quickly. To play fast, you need to minimize how much you lift your fingers off the notes, so you are wasting less time with inefficient or excessive movement in your fingers. You not only need what I term as ‘minimal movement’ to play fast, but fast and accurately. Learning to play a variety of scales will certainly help with this.
Being able to play scales is also useful for playing the piano in different types of genres. Classical music can often contain scale like sections, which are made much easier if you already know the scale of the key of that particular piece. With modern or jazz music, being able to add the scale or a part of the scale to your playing, adds an extra level of interest to the overall sound of the piece of music.
Playing scales, while seen as not the most exciting or interesting aspect of learning to play the piano, is certainly helpful in enhancing your ability to play the piano.