: But you always pay 0.85% for the TA in the 1st phase on the full amount, since no repayments are made. So, a classic annuity loan at 0.85% would be cheaper (at least for the first 10 years).
A building savings contract is primarily a bet that interest rates will rise in the future (otherwise, only the building savings advisor has benefited), and it cushions (or excludes) the risk.
Secondly, building savings contracts are also useful for leveraging equity in financing, since the building savings contract is subordinate (or, under certain building savings contract amounts, even unsecured). In other words, it can be worthwhile to include a building savings contract for the loan-to-value ratio, which might make the main loan cheaper.
And thirdly, if you are into Riester, you can nicely incorporate your subsidies into financing.