Pros's:
They have a portable wifi hot spot that you can take outside with you in case you didn't bring a phone with international roaming.
They have an outlet that's compatible with US chargers, so you don't need an adapter.
Everything is remote control. You can also control the light switch which is in reach of the bed.
The bath tub/shower can get we hot as you can stand it.
They provide multiple blankets which are all super warm.
They have laminated booklets full of useful information, as well as signs posted everywhere answering any question you may have (inc the wifi password!).
They have tons of toiletries, teas, etc. with little signs that say not to be afraid to ask for re-fills.
They have a fancy blow-dryer.
The kind host came to our door and invited us upstairs in the morning for tea with his wife to take pictures and just to discuss our travels (They live upstairs). So we will be getting an authentic Japanese meeting, which is amazing.
Con's
Cold (thermostat was right by the bed but didn't really hest anything but the bedroom, maybe there was another thermostat we just missed).
Was hard to find without our phones. We had to ask locals for help, but that's on us. Make sure to download the password to unlock the door before you leave the country if you won't be using a Japanese sim card, because to open the link with the code requires data/wifi.
Bathtub was small. I like it though, but if you are on the bigger side, you probably won't fit.
I also didn't like that the mirror was by the kitchen instead of the bathroom. Not a huge deal to most but it's a pet peeve of mine.
Bed was twin size, but it was just enough space for 2 people who like to snuggle :)
The host wanted to make photocopies of our passports, which we declined for security reasons; We do not feel comfortable with other people having our passport information and have never needed to give it out before (We've stayed in plenty of air bnbs throughout the world).