Very good Airbnb if you are only planning to use it as a place to sleep. Shower / Bathroom is shared and you can tell. It depends on the guests who are staying there for the moment to be tidy & clean because, well, it's an Airbnb. There is no one at the location 24/7 to permanently look after everything. It's perfectly fine, but if you are unlucky with other guests staying there while you are there too, it might turn into a bad experience.
I'd recommend looking at the shower ceiling and maybe generally renovate a bit to get rid of the rustical / old building feeling.
The staff I had an interaction with (was looking for someone who extended their stay, but there was a mixup in rooms) was very nice and luckily spoke good enough English to clear things up after speaking to the Owner/Boss - definitely keep her, staff that understands / speaks English is very valuable here in Japan!