Both. I’m not super familiar with it because by the time they got around to releasing an artificer I was already waning in my 5e interest, so I’m going largely on memory of early drafts (Unearthed Arcanas) and general cultural osmosis.

Different subclasses or builds have different focuses. There’s an alchemist subclass, a gunner subclass (like 2e’s gunslinger), and one more like the inventor.

Makes me wish there was an English word for “Schadenfreude”

The thing is that the inside lock can always be bypassed by from the outside by staff. One of the best measures against that is a little strap that makes it possible to physically keep the little latch in place. When it’s overwritten it normally snaps back, but that strap keeps it in place.
Protecting against staff is one thought, also against people who really want to get in your room like abusive partners and such.
I totally understand why being in a room that for a fact can easily be opened by a stranger can be quite unsettling to people, especially women.