|building = *|
|Using this tag is discouraged, use building=yes instead.|
|Used on these elements|
|Tools for this tag|
There is no value whatsoever in using building=* instead building=yes. Meaning is the same, it just makes it harder to support it by various tools. For example StreetComplete will ask about building type for building=yes, it will not happen with this building type.
As bonus "*" character in text like "building=*" is often used in meaning "any value". It makes using "*" as a value especially confusing.