Still yet another Fifth Beatle. This one advocated by Derek Taylor for his quirkiness, his outside-the-box-ness, and his honey voice.
But this one makes no artistic sense. Where for instance Murray Kaufman was a living link to the black music The Boys revered, this one's pedigree seems so mainstream, so showbiz and Hollywood, his aesthetic drenched in that syrupy treacle they rejected and refused in their own music. He was a Pop Star. So?
Maybe the link was more counter-cultural than artistic. So that what he brought to them was Los Angeles Party Central, and the bond was about drugs and fun. Seems that way, from the anecdotes.