Is there any other legit reason to shoot black and white other than aesthetics? I’d argue that yes, there is. Black and white photography encourages you to think more about lighting, tones, dynamic range and composition. Black and white is really good for improving your photography and as a learning method it’s really beneficial.
In some ways black and white is harder than colour photography, because, for example, you can’t rely on colour contrast to give you separation with elements within the photo. On the other hand it is seemingly easier, because it has a certain kind of stylishness that goes with it. Why are black and white photos considered to be generally more stylish than colour? Well, science hasn’t been able to explain that yet, but we all know it’s true. Some times you can actually try to save a relatively crappy image by a black and white conversion.
In general, shooting on black and white will force you to think more about tones and light in it’s purest form. I’d say when you master that, it’ll be beneficial for colour work as well. The underlying fundamentals are the same either way, but they are harder to detect when shooting colour. Why you may ask? We see in colour and colour differences in our field of vision help us to make sense of what we are seeing. Even in totally flat or poor light, different colour items are easily separateable in our eyes. The same view in black and white reveals that now the elements are, in fact, just the same tone of grey. Now, in order to get a better separation between them, they need to be different tone compared to each other. That can be achieved very effectively by the way they are lit. When you remove colour usage from your arsenal, you will need to think harder about tonality and you will learn to take better photos.