This is essentially legalizing 'squatters'. If people are renting a house for example, and they claim residency over a certain number of months or years, especially without paying rent, eventually they can claim defacto ownership of the property.
It may or may not hold up in court, but it will extend their time on the property. And even if they lose, it will still take months and a whole platoon of constables and police to get them out.
Biden knows this, and he has said that interfering with the private use of the owners of private property was his goal in doing this.