In Berlin your rent will most surely be less than mortgage payment unless you take a very very long mortgage (like 50 years). Plus you need a down payment.
The reason it makes sense for landlords is that they have nothing else to do with the money if interest rate is zero or close to it - the alternative is slowly losing it (or higher risk stuff like stocks).
So they slowly build equity while not profiting every month, counting on prices continuing to rise for their long-term profit and if they run several properties you can get economies of scale going for managing them.
The reason it makes sense for landlords is that they have nothing else to do with the money if interest rate is zero or close to it - the alternative is slowly losing it (or higher risk stuff like stocks).
So they slowly build equity while not profiting every month, counting on prices continuing to rise for their long-term profit and if they run several properties you can get economies of scale going for managing them.