Second residential unit in the house due to KfW funding 153

A modest question.

Why
Are you all so eager for a KFW loan?
Okay, there is a repayment grant, but in terms of the interest, only the 10-year fixed interest period is worthwhile.

I am also building 2 residential units but will probably completely forgo the KFW loans.

I could get 200,000 euros at KFW 40 but have to pay everything off in 10 years or hope that the interest rate is still low in 10 years.

I prefer to finance the entire amount without subsidies with at least a 20-year fixed interest period.
Maybe I am just too focused on security.

, we completed the financing in the middle of last year, when interest rates were still attractive. Now we would probably finance differently.