From a status standpoint, I think crediting to AF would give an advantage. Assuming US membership, it's 25000 level miles for Silver, 40000 level miles for Gold, and 70000 level miles for Platinum in Flying Blue. This compares to 25000/50000/75000 on DL.

If the flights are mostly/all on AF, I would also expect AF will probably take care of their own elites in various situations slightly ahead of other SkyTeam elites.

There is a forum for Air France/KLM Flying Blue, so looking there for more details would be a good next step.