I agree AF is chipping away at its USPs if it introduces Bob. Nonetheless, there are many BoB models AF could choose from.
They could for example dole out free drinks ans snacks to all Plats and Golds. That would be a way of retaining loyalty and even increasing it, because the feeling of "being special" versus other pax would increase.
I flew FR last week and preordered a drink/snack and it was nice to have the crew coming over to serve me before everyone else. That said, the rest of the flight experience was plainly inferior.