It’s traditional for a Republican President to have one or two Democrats in the Cabinet (and vice versa). In recent years, this has been achieved often through hold-overs from the departing President’s cabinet, but it isn’t easy to think of a member of Obama’s cabinet who would be willing or acceptable given the scope of regulatory and policy changes Obama has promised.
Gabbard isn’t good but she’s not as bad as most Democrats. Appointing an Asian-American Buddhist woman wins some points too, I guess, although in a game Trump will never win anyway.
I doubt she has any interest in the Trump cabinet. She’s shooting a lot higher than that.