I'll give this one a stab. No, this job won't be looked better upon because of it's applicability. In fact, it's not really applicable at all, and if you're under the impression that it is, you might want to do more research about the what the actual future career you're getting into really is. As an officer in the Coast Guard, you won't be swimming to rescue people from the water (and even as enlisted, unless you're an AST/rescue swimmer, the odds are remarkably low), and you more than likely won't be providing first aid or pumping, that will almost certainly be done by a Health Services Technician or AST or some other enlisted if not. Performing first aid is more likely than swimming, though, but still, absolutely no requirement to hold a certification or anything like that. Additionally, if there was, it would be provided if needed.
However, Cadets at the Academy do take a class on lifeguarding, because there are good skills there for anyone to know, and because the 2/c Cadre serve as the lifeguards for the 4/c Swabs in swim class.
With all of this said, while I don't believe it will be looked especially well upon because of "applicability," it may be looked better upon because of the responsibility and independence of the job as opposed to where you've held jobs in the past.
If I've misunderstood your meaning, I apologize. But seriously, if you think being an officer in the Coast Guard and being a lifeguard are going to be super similar jobs, definitely do some more research before deciding to apply.