I disagree,
far be it for you or me, MACCOLL[or anyone else   to tell other singers what they should do,.
as someone who has had considerable experience of performing, I would say this,the art of performing lies in communicating with the audience [there are many different ways of achieving this]laughter [providing the singer is not taking the piss out of his material]is one of the most successful ways of winning an audience over.
examples Dave Burland,Martin Wyndham Read, Hughie Jones. Now if presenting a cabaret act[ Ewan Macoll did this too[[he and peggys show was a very well planned caberet act, to the extent that he discouraged any support acts,in case it didnt fit in with their show]]enables the performer to communicate the songs,examples maccoll, mike harding[he sings good quality serious songs too]TheSPINNERS ,Hughie Jones the Ian Campbell group.Isee nothing wrong with that.