This is actually the only move they could make. They last floated Idris Elba as the next bond. Pushback was SIGNIFICANT primarily due to him being black. So they were stuck, couldn't have Craig continue and save face, couldn't put up another white actor.....Hmmmm. Need a new plan.
She isn't the next Bond, in fact Craig is in the movie as Bond, a retired Bond, so no longer 007. She is a new spy, a new 007
Gives them two possible paths, actually 3:
1) She fails, they still have Bond to fall back to
2) She succeeds, Bond can stay retired
3) New franchise in a later timeline than Bond, keep Bond going
