I would mainly echo what other reviewers have said – the biggest positive for me was the CHARM of the little place. It's sort of like a writer's hideaway with elements of 1950s/early 1960s touches (such as an old manual typewriter, record album cover from some old-school musical artist, some of the old funky furniture, etc.). For me, what it lacks in space, it makes up in charm.
I would say the biggest PROs would be the charm, the basic location for an AirBnB being in the middle of the Hollywood Hills, The look of the front yard and cave-like vibe, as you approach the front door (as seen in the pictures advertising the location).
As somebody who likes to jog in unusual or unique locations as I travel, it was A very cool doing a nice job through the Hollywood Hills making my way a little over 4 miles down to the Sunset strip. This would be unique to someone who likes to jog (or walk) a fair distance to get somewhere, through the unique area. There's nothing quite like walking/jogging through this fairly upscale hilly area of So-Cal.
It's also fairly quiet, for the most part.
As for CONs, Some of these would be depending on the person and what you're looking for.
The main thing would probably be the fact that there are no coffee shops, restaurants etc. really within walking distance and it would really only be a place to sleep and/or a retreat, etc. It's not like you can walk within a mile or two of the "hotel" and then think, "Oh, let me walk back to the room to grab my jacket." (Once you hit the town, you want to make sure that you don't leave anything behind, otherwise you have to get in your car and drive through the hills a bit, to get back to the location - It truly is a "Hideaway" :-)
Another con would be the raised "bedroom" area being so very small – think about getting into a small bed located in a small camper; although the ceiling is (maybe) taller than some campers, there literally is no space to walk around the bed (as the small, single mattress fits squarely in it's space (although there are little little wooden shelves, on which you can put a bottle of water, your eyeglasses, etc.
Also it's a bit of a big step down Into the little living room, when you might need to go to the bathroom in the middle of the night.
I didn't have a car, but parking could be a little bit of an issue.
If you like the idea little hideaway in the Hollywood Hills but are okay with not being close to amenities nearby, it's potentially a lot of fun. For me, Although I wouldn't choose to stay there if I were let's say staying in LA for a week or 2, for a couple nights, it was a hoot and enjoyable.