How secure is the collateralization of the remaining debt via a home savings contract?

Hello everyone,

our financing has been applied for. 380k over 15 years with 4% interest as 100% financing. Remaining debt 190k if no special repayment is included in the annuity.

For the remaining debt, I wanted to take out a building savings contract, I could still get it at 1.15% interest on the building savings loan.

What worries me is that it might not be allocated when needed. According to the advisor, "no problem at all," it would be allocated from a savings amount of 50k. That would not fully cover the remaining debt yet, but that is the amount we definitely feel confident about during this time - room for improvement.
We want to have completely paid off the remaining debt with the building savings contract after the 15 years.

There are stories on the internet about building savings contracts not being allocated, which makes me somewhat anxious. Does anyone here have experience or expertise, either to advise me against it or to relieve my concern?

Here comes someone again with a building savings contract.
Last time, no one could plausibly explain to me how it exactly works.
Maybe here?

Leave that nonsense, it only brings a connection fee for the broker. Finance the 190k after 15 years through savings or traditionally. What are 190k still worth in 15 years?

Here comes someone again with a building savings contract.
Last time, no one was able to explain to me plausibly how it exactly works.
Maybe here?

You save into the building savings contract over a period, with us the term of the loan. When it is then allocated, you receive 1.5 times your savings amount as a building savings loan on top - at the exact interest rate of 1.15% that I mentioned above.

With the disbursed amount, I repay the remaining debt of the annuity, and afterward the building savings loan is paid back. The installment is measured in per mille of the building savings amount. Special repayments are possible at any time and as often as you like.

First of all... do you have the money left to finance a building savings contract [Bausparvertrag] in addition to the installment and is it more worthwhile than an early repayment? After all, we're talking about ~80k that you additionally have to save, so over €400/month. Secondly: If you make an early repayment from the [Bausparvertrag] part, you have very little residual debt and really nothing to fear. Thirdly: Nothing is guaranteed with the [Bausparvertrag]. Usually it is allocated, but the devil is in the details. Conclusion: I also don't see the point.

First of all... do you have the money left over to finance a building savings contract in addition to the installment, and is that more worthwhile than a special repayment? After all, we're talking about ~80k that you have to save additionally, so over €400/month Secondly: If you make a special repayment from the building savings contract part, you have very little remaining debt and really nothing to fear.

Thirdly: Nothing is guaranteed with the building savings contract. Usually it is allocated, but the devil is in the details.

Conclusion: I also don’t see the point.

The point lies in the guaranteed (low!) interest at the end. Whether that was really necessary you only know afterwards.

Yes, we can afford it. But at the beginning there is still a bit to do on the house and then to organize a wedding party. So the plan is that it will be fully paid off by us after about two years through annual special payments. For now, monthly payments are just enough to keep it alive.

We are financing well BELOW our theoretical means, while there are no children and none are planned in the future. Nevertheless, I am looking for a middle ground between security and the cost of security.