They are freeing up ~10,000 houses over the next four years with this legislation. Barcelona built ~15,000 new properties between 2011 and 2020.
The math don't math. It's a drop in the bucket. The entire impact of AirBnB + all housing built in the last decade does not offset the last half decade of population growth.
Housing must be built more quickly than your population is growing to keep prices down, or you must concede that you live in a nice area where people wealthier than you wish to be and that those people are going to gentrify the area and displace locals. It's an unpleasant reality of the world.
EDIT: some good feedback in the responses. thanks! I'm being a bit dramatic by saying it's just a drop in the bucket, this action frees up more housing than was built over the same timespan, and it's possible to have effects on pricing greater than what would be inferred by the raw numbers because economics is tricky. cheers.
Extreme height restrictions combined with extreme regulatory costs is what has lead to this issue.
Show a European politician, especially a local one in charge of urban development, an image from Tokyo and they will recoil in horror.
Here in Europe everything must be flat and look cultural.
Spain seems to have planning laws that force density. Small agricultural towns in the middle of nowhere have people living cheek by jowl in apartments and townhouses, with an abrupt cutoff once you hit the town boundary.