That is a rejected insurance claim waiting to happen.
I mean, imagine coming home to find out it had a hole and leaked all over the place while you were out.
Next you'll be telling me that the neighbor installed a hot tub in his apartment and it ended up shorting out the building's electricity, causing me to miss a very important alarm.
I set my bath pillow on fire once - while I was in the bath. I was well impressed with my quick thinking just to yank in down into the bathwater to put it out. My partner was too unimpressed with my stupidity/carelessness to appreciate my quick reflexes!
Would this truly be the suggested set up though? An inflatable pool in your dining room? I used to have hydrotherapy until I found it too difficult to actually get there. They recommended warm baths, not that I DIY one in my house!
This setup in the image looks crampy and sketchy, but in general the property owner build and maintain the pool and rent it to hydrotherapy therapists (or use it for its own such business). Normally (well, excluding cases we see in this community) one does not build one just for themselves in their livingroom or kitchen.
Indoor-issues aside, I get the feeling that people who would be willing to do this, probably wouldn't care too much about the water quality either. How often are they cleaning or replacing the water? Do they still go in it even if it's not being cleaned regularly? What does this smell like?