On the margin, that’s likely to reduce the supply of rental properties at a given price. Whether that’s good or bad on balance is an open question, because renting is clearly advantageous for many people, while ownership better for others.

I assumed it would not apply to multi-unit properties but only to single-family houses.

Around here (Cambridge, MA [and Somerville]), a very typical rental is in a 3-family, sometimes a 2 or 4 family. It’s fairy unusual to be able to rent a single-family here (there aren’t very many available for rent).