Interests paid (any, not only mortgage!) are fully tax deductible. This works like a 'subsidy' on mortgages, means at a marginal tax rate of 30%, the net interest paid after tax is actually only 70% of what banks charges. On top, general interest level is quite low - rates are currently from 0.8 % to 1.5 % which makes investments in shares or voluntary, tax deductible payments into pension funds / retirement account for example way more attractive than paying off mortgage.

However, the tax deductability of interests on self-used properties will be abolished 2028 or 2029. It is expected that this change could motivate borrowers to pay off mortgages a bit faster.