Anything that breaks a straight line usually costs money. Bay windows, recesses, setbacks, cut-off corners, dormer windows, etc. Basements cost money and, in some cases (if not used sensibly), are a waste of money. With sensible and regular use, a basement is an advantage.
I think the idea is good to summarize where you might be able to save a few euros. But it’s typical again how everything is spoken badly at first, typically German after all.... The only example that comes to mind spontaneously is that I am currently considering whether a strip foundation makes more sense than a slab foundation for a garage.