[munificent]

There are definitely good reasons to high pass at something low like 20 Hz. Very low frequency signals eat up a lot of headroom, make speakers work harder, and make it more likely to encounter distortion during parts of the signal path, all for zero audible benefit.

Having what is practically a DC offset in your signal doesn't do anyone any good.

[duped]

There's definitely good reasons to do it, they're just kind of rare to see in a modern digital stack. DC offset is hard to introduce unintentionally and subsonic content is usually removed early in the mix, not on the master (if they aren't, it's arguable a bad mix).