Nautical terminology is perhaps the oldest jargon in the
English language, so old that it actually evolved a bit separately from modern
english from a common middle-english root.
Jargon in all fields has the goal of increased precision in communication, but is generally used more to convey mastery of and status in the subject matter rather than to impart real precision. I
work in information technology, which is also steeped in its own specific jargon, so I have to put up with tiresome jargon-infested dominance displays daily.
If you want to use language precisely, then you should use nautical terms for nautical things. This is especially important when
crewing with strangers, because words like port and starboard mean entirely different things than left and right, and because knowing the specific names of objects is critical to
safety. Referring to
sheets by color is a really hassle in an
emergency.
If you want to be understood by non-experts, then you should use the terms they will understand. I tend to respect the listener by speaking to them in terms they'll understand and not presuming to teach unless I've been asked to act in that role, which I do assume to be the case when I'm introducing people to sailing. But if they're going to work with me, they need to be competent in the jargon of the work. Otherwise they're just passengers.
I joined the Navy at age 18 and have been using nautical terminology my entire adult life, as it is required for shipboard life, so I find it quite natural and have taught my
children to use nautical terminology onboard our
boat. But I switch immediately away from it when my goal is to be understood. And we don't use some of the
toilet terms that are common in the Navy.
To the immediate subject, a stateroom is a centuries-old term for a senior officer's quarters on a ship and specifically refers to a compartment (not room) which is not shared with anyone other than than perhaps the captain's spouse if aboard. That is what makes it distinct from a
cabin, which is a shared berthing.
Junior officers shared cabins (although they often referred to them as their staterooms), which are multi-person but still relatively private and small compartments.
Enlisted crew slept in berthings, were large open-space multi-person sleeping compartments.
There's no specific meaning on private recreational craft other than superficial similarity to those compartments on larger professionally crewed ships. I think a reasonable distinction for private
boats would be that a stateroom includes a private
head, and a
cabin does not. I would call anything with more than one rack (bunk) a berthing.