Not necessary, but inevitable.
The Angels were a last-minute fill-in. They originally wanted to use the girls of "What Happening" (Mom, Dee and Shirley) but with Shirley Hemphill the pig analogy hit too close to home.
A long time ago, I secretly decided that Tennille was was much hipper than her hairstyle and Sears-Off-the-Rack clothing would suggest. Start by turning "Muskrat Love" into a metaphor about another small, furry thing and the rest is easy.
A necessary evil. I consider it a cautionary tale.
The Horror! Jx
I always had a thing for the Captain's belladonna eyes....
Of course you did, darling.