The relevant quotes from Kersee, from:
“I think the goal is she needs to be under 3:59 or better to really get the benefit out of the 1,500 and with her speed ability to get the ultimate transfer to the 800 in order to break that other 30-year-old (plus) record at 800 meters,”Kersee said.
“I just think when she has that, that anaerobic threshold and being able to hold over that and take the 800 out at a decent speed, that’s going to allow her to go under 1:53.”
“The 800/1500 or 400/800 has been done and I think Athing has that ability and I think if the schedule allows it, it would be nice to see for a woman to double the 8 and 15 at a very high level with the potential to gold medal in both,” Kersee said.
So I think the first bit is right, getting her to 3:59 shape to challenge the WR is a good idea.
The last bit about medalling in both is a bit of hyperbole as long as Faith Kipyegon exists, in my opinion.