They are normally inaccessible to people who don't already own their own property, even more so by the nature of the higher than usual deposit required, so it's an investment vehicle for already well off people to leverage more money into property and extract money from tenants
It puts upwards pressure on housing prices because you don't just get the family that wants to own a home or the occasional landlord who wants to own and rent out a second holiday house, it's a purely synthetic financial product that lets you take a house out of the market and arbitrage on the difference between your interest payments and the tenant's rent
It is not uncommon for people like this to own tens or hundreds of properties in their portfolio this way, and these are the people crying first and loudest when interest rates go up because their rental yields can no longer cover the interest only payments on the houses they "own". Whatever happened to being on the hook for bad investment decisions? They think they should get special treatment because they're providing a so called service to the tenants
But even on a traditional mortgage, in the early years the vast majority of the payment is interest. How much lower is the monthly payment on an interest-only loan? Are they easier to qualify for? Are the rates the same, or higher than, a traditional mortgage?
I'm not sure I'd want to ban types of financing for types of properties, that seems heavy-handed.