This depends on what you pay, how much you can rent it for and what your costs are. I live in a Rocky Mountain resort town in the U.S. and own vacation rentals. They can be very good investments however, if you are renting remotely you will need a property manager and, at least where I live, they take 45-50% (might be less if you do all the booking) of rental income to market the property, book renters, clean the home, repair stuff, deal with renter's needs etc...That doesn't cashflow for me so I manage my own, but I live in the same town as my rentals.
As far as the 28 day discount, this is because in many towns a rental period of one month or more is considered long term and is not subject to sales and lodging taxes as well as other restrictions. Anything shorter is a vacation rental and subject to taxes, local short term licenses and zoning rules. Properties can only be rented short term in specific areas (to prevent displacement of local working communities/neighborhoods).
Owning a vacation rental is owning small business. If you are going to buy a home some place anyway the rentals may offset some of your mortgage and tax costs, but to make it cashflow and provide good returns you will have to treat it like a business.