Quite simple. If the property belongs solely to you, you can do whatever you want with it. If it belongs to you together with others, your rights are at least limited. In the [WEG], a "special agent" is enough and you have 30 years of fun because all structural matters must be decided together, even if you (like in the 6-person constellation as the first in line with the fence from the sixth) are not directly affected.
The insidious thing is – you don’t even know the owner composition when you buy and you have no influence on who might "buy in" through ownership changes.
As a surveyor, you can let it run like that without worry. If, later on, properties are separated from the 6-person parcel because it no longer works, it is definitely more expensive than if you separate it properly before construction begins. It gets really bad if division is no longer possible.
Honestly, I can hardly imagine savings with the notary/land registry, but it is possible; I do not want to exclude that. However, the fact is that due to the lack of division, more properties, owners, and thus rights have to be interwoven and mutually secured.
The division costs cannot be precisely quantified without knowledge of the layout, but especially with multiple properties, costs quickly drop to a manageable level. In return, you then have peace of mind separately.
Best regards Dirk Grafe