What's the difference between a hyphen and a comma when adding context into sentences?
> The kid ran awaywith surprising speed for his agebut he failed to outrun the car. > The kid ran away - with surprising speed for his age - but he failed to outrun the car. Here, emphasis is put on the additional information. It stands out. Both of these are the same. > The kid ran away, with surprising speed for his age, but he failed to outrun the car. Here, there isn't any particular emphasis, it's just extra info. > The kid ran away (with surprising speed for his age) but he failed to outrun the car. Here, you draw attention away from the extra info, it's a bit like saying 'this is not too important, but it's there'.