When 'twaddle' is used, it usually shows that the speaker thinks lowly of what is being discussed. Don't waste time reading that book; it's pure twaddle.
Pro Tip 2/3
Informal Context
'Twaddle' is informal, so avoid it in formal writing or speeches unless quoting someone. In the meeting, he whispered to me that the proposal was twaddle.
Pro Tip 3/3
Negative Connotation
Using 'twaddle' has a negative connotation, suggesting something is pointless and unworthy. The debate turned into twaddle; nothing meaningful was said.