There are other technologies for reducing CDE then dropping a concrete slug. The GBU-39B and the BLU126/B are two examples of low-collateral damage bombs that use a reduced amount of explosive filling and, in the case of the GBU-39B at least, uses a casing that is designed to fragment into almost non-lethal components.
My main critique of this goes back to the threat. Beyond killing small pirate type boats, dropping a "smart bomb" on any sort of target that has an active AD capability is going to be sub-optimal. Standoff is the way to go with this sort of stuff and if USAF really wants to creep into the USN realm of destroying ships, they should put some energy into developing systems that will enable their aircraft to carry the anti-ship designed missiles such as the AGM-84 Harpoon. If they are really only concerned about pirate ships with no AD capability then why not just use 20mm or have those beautiful A-10's that they want to get rid of flying around shooting boats with the 30mm? (not a serious suggestion) Even better, just let the USN handle anti-ship strike. I'm unconvinced that this is a skill set that is in short supply and that USAF needs to be demonstrating a capability to deliver.
The argument may make more sense in Canada for sovereignty issues seeing as our Navy does not possess an organic "air arm" beyond rotary wing but I don't think there's much of a pirate threat in Canada unless I've missed some news stories about some Great Lakes Pirates where, incidentally, thanks to the Rush - Bagot Agreement of 1818 limiting our Navy to only two ships with one gun on the lakes. (tongue in cheek)