IMO the DS is positioning Buttigieg for the WH. Not sure if the goal is to put him there in 2020 or if they are just prepping him for a future run.
NeonRevolt had an EXCELLENT column on the topic. Very, very, very long and covered a lot of ground but well worth the time to read it.
Buttigig has as much chance of being president as (crude language alert!) my left butt cheek has.