Sure, many people like that style, I don't. But no, I don't think there are any downsides, but there is this notion that things should look like what they are,

Sure, many people like that style, I don't. But no, I don't think there are any downsides, but there is this notion that things should look like what they are, which is popular in C. With parens, I would suggest spaces to make it sizeof (*f->buf) that makes it look less like a function call in many styles.