We currently also still have 30m2 of living space in the basement. Only - that is dead space. No one uses the rooms (guest room and office) or only sporadically.
And a house can also be built a bit higher even without a basement. After all, there is still a slab underneath. We have exactly one step from the house to the street (or we can also do the whole thing without a step if we make the path a bit diagonal) and the terrace will also be a bit higher than the garden.