Super Mario Bros 3: breaking underwater blocks

Rather than just simply say a boring "there's no way to break this block" I think I'll mention that the block appears to be there only to be in the path of the 1Ups that come out of the blocks to the left.

Presumably, if you fail to catch these 1Ups as they drop down they will bump into this block and return to you without having to cross paths of the nearby Berthas before collecting them.

Perhaps just a hint of mercy from the developers? On the other hand, they could have used a non-breakable block type for this to prevent any confusion about it's contents and we likely wouldn't be discussing it today.