VAIN promises on beauty jars

[Relayer211]

       I was thinking about "sweet bird",and I looked up the word '"Vain" in 
the dictionary. The first definition is "conceited, especially about one's 
appearence".the second definition is "having no value or signifigance,as in 
'vain triumphs'."

       It occurred to me that the use of "vain" in "Sweet bird" may have been 
a clever play on words by Joni,her using the word "vain" to convey 2 meanings 
at the same time. Am I correct?