Regulations where you'd specify minimum floor size, or rooms per person make sense for me. It's about straight up saying you can't live with people without state sanctioning the relationship.
In my region, the rules are so incredibly precise. Things like washing up areas must have at least 3 bowels in. Toilets must have flush handles above a certain height and below another height. Radiators must have 6 heat settings... Etc.
The entire aim seems to be to make running such a house not illegal, but very difficult and very expensive.
Precise laws are usually because enumerating every single bad alternative is an issue, so they just tell you what is permissible.
Besides, such specificity is usually drawn from building code best practices, which advocate for standardization. Which means that manufacturers don't bother creating radiators with less than six heat settings.
Usually you need to get a special license, have home inspections annually, pay various fees, etc. if you want to do so.