OK, just so we are all on the same page: legally, IRT the US Government, "Armed Forces"and “Uniformed Services” refers to certain very specific organizations under the command of the Prez, subject to the UCMJ, using a standardized paygrade structure, etc. That an organization bears arms, like the ATF, or that it wears uniforms, like the Border Patrol, or even that it flies AWACS-equipped P-3s, like Customs, does not make them one.
The US Armed Forces, aka Military Services, are the Army, Air Force, Navy, Marine Corps (all under DoD) and Coast Guard (under DoT, proposed to be under HomeSec).
The Uniformed Services IIRC are those five plus the Public Health Service (under HHS) and the NOAA Corps (under Dept. of Commerce).
USCG does deploy around the world, to show the flag, to cooperate with friendly nations in developing their coast guards or navies, and to cooperate with friendly nations in stopping smuggling at the starting rather than end point. The “Coast” name was adequate in the 1920s or so when they merged the Revenue Cutter Service, Lighthouse Service and Lifeboat Service, all of which were “coastal”; but maybe something like “Maritime Guard” would have been more appropriate to what they evolved into.
The Coast Guard does provide frontline, military, combat service in specialized roles. During WW2 service they operated landing craft. In Vietnam they provided littoral-warfare assets (patrol boats) to fill the gap between the Navy’s river-patrol craft and high-seas ships, and exchanged fire with the enemy, incurring casualties. Until the mid-late 80s they did have ASW capabilities. However it was decided to better husband their very limited resources into what they do best – for one, modern warfighting systems work best when integrated as a whole aboard a custom-made specialized combatant like a Perry-class frigate or a Burke-class destroyer, and not so well when tacked on to a general-purpose platform that also has to do law-enforcement/rescue/research/environmental-protection jobs (and in peacetime they mostly just sit there using up space and resources). They just recently announced a plan to do a full update of their assets, and about time – the cutters and planes have been getting long in the tooth and spread thin.