I know the Coast Guard does not need our aircraft to land on the water very often but sometimes there is no substitute and there might be additional justification.
The potential advantages for medical evacuations are obvious, but thinking outside the box maybe US Special Operation Command (USSOCOM) might want the Coast Guard to have a few of these so that they could barrow one occasionally.
USSOCOM identified a need for something similar and looked at creating a MC-130J Amphibious Capability (MAC) but that program is on hold.
A rendering of a C-130 floatplane previously released in relation to the MAC project. USAF
Potential dual use makes acquiring the capability more attractive. Coast Guard markings might even provide a cover story for deploying the aircraft. A MAC flown only by USSOCOM would be a bit of a give away.
Thanks to Sven for getting me to think about this.
Chuck Hill's CG Blog 
If I were picking Japanese kit to invest in, I would take their slow production of these planes over having them build our ships.
Not likely to happen! Japan doesn’t license their military proprietary products rights to other countries! They’ll be happy to sell their ShinMaywa US-2 seaplane as long as ShinMaywa constructs each and everyone of them! But Japan won’t license their proprietary products ShinMaywa US-2 design to the United States or to any other country…
Japan has gotten more liberal about this lately. We don’t need to build it in the US.
Liberal or not, the Japanese aircrafts industry tend to have slow production rates in producing aircrafts, one of them being the ShinMaywa US-2 amphibian…
I’ve always thought we could upgrade the old Consolidated PBY Catalina design.Modern construction methods like CF reinforced aluminum, turboprop engines, and wing mounted SAR gear. We could probably squeeze a bit more performance out of the wings by mounting the engines “on top” like the old German BV-138 and Russian An-32. That would allow for larger props and better STOL numbers.I’m willing to bet we could barrow most of the needed systems directly from the HC-144 to reduce training time and product line burdens.
The Consolidated PBY Catalina was adequate for its time and superseded by more modern seaplanes during that latter stages of WW2 and post war requirements made the Catalina obsolete! But several privately owned companies did replace the radial engines with turboprops to fill private and commercial niches…
There is literally a company doing this. https://catalinaaircrafttrust.com/ngaa-home
U.S. Navy success in the Pacific in war has been largely a product heavily influenced by amphibious aircraft. The U.S. Navy should return to this model. Helicopters are good, but they do not have the range, ability to land on water typically, and aviators will need this during Pacific conflict in the future.
haven’t seen an updated brochure but Viking – no back under De Haviland Canada, offered a multi-mission version of the CL-515
https://volunteerfirefighters.org.au/wp-content/uploads/2020/08/cl-515fr_ds_specsheet_01-20_0.pdf