I stick to my point: Hereditary building rights are a way to acquire quasi ownership rights with a very low monthly burden. That the municipality in this case also provides for 20 years of self-use further suggests to me that they want to do something for the less solvent families.
That was the claim 110 years ago in the German Empire, when this supposedly very consumer-friendly regulation was invented.
I also maintain that in the current situation paying 3% (reduced) and after 10 years 4% on a current market value (real example), and fixing this ratio for 99 years - while simultaneously locking in the indexed lease increase, is madness. One could discuss it at 0.5% - 1% interest.
For the budget, the whole thing is still irrelevant in the first years - the loan for the house plus the ground lease for the land or simply more loan for house and land. But while one pays and repays for the land, the hereditary leaseholder only pays.
From a post further up - today the land may be worth €250,000, in 75 years maybe €1,000,000 - and the leaseholder has paid AT LEAST 75*€6100. If it is not normally increased according to index. Calculating an average 2% increase over 75 years, one quickly figures out for whom this business really pays off and for whom not. It is a model from the German Empire, and was never intended to benefit the common citizen.