It is just the English sentence that means it resolves to a number or datetime or something that has a well known order to it (i.e. 10 > 20) or 10:00 1/1/2020 < 11:00 1/1/2020). It might be better to explain or define it better since some might think a string could also have a well known order to it (but maybe not all agree on what the order for strings would be)

7.7.3 FilterOperator

Added clarification:
Operands that resolve to an ordered value are restricted to the DataTypes Byte, Int16, Int32, Int64, SByte, UInt16, UInt32, UInt64, Float, Double and DateTime.

Agreed to changes in Virtual F2F.