I took it as showing the instability/stress of the relationship or like a home movie effect, but either way it is pretty distracting. I think he just likes stylizing things to call attention to themselves, this is a guy who added Von to his name in film school to sound more interesting.
i thought something along those lines too. but yeah ultimately it ends up being more distracting than anything else for me and i'm just reminded of all the stupid "stylizations" and bad editing that were in Nymphomaniac. that might have seriously just poisoned me against von Trier forever lol