Power Query , Combine Columns how combiner works

Hi,
Can someone help with this if I have two columns to combine and the is an empty cell in one column when combine
using Text.cobine ignores the delimiter and just returns the one value , but a combiner adds the delimterter to the singel value,

 iTable.CombineColumns(  Source, { "ColA", "ColB"},   each Text.Combine(_, "-") ,"N") 

and 

able.CombineColumns( Source, { "ColA", "ColB"}, each Combiner.CombineTextByDelimiter("-")  (_)  , "N")

so Question 1) why does a = just text and b = delimiter plus text when there is an empty cell I thought it might be to do with quote style but only guessing, and 2)
can a splitter. be made to behave like text.combine? I have attached the example of the two

Thanks,

RD