Even if it holds just 1 record, it's not a waste. Most of our databases usually have only 1 record in _ExtendedProperties. The main advantage (for us) is uniformity. We have this basic database layout, we have a .NET library for data access, which has
a Database-class, which has methods like GetExtendedProperty and SetExtendedProperty that makes it really easy to store and retrieve single pieces of data from .NET code.