i should have added that , in my case, i had family emergency and needed to head back home fast and was able to do it as i had the spouse visa and I 551 stamp
with a K1 I could not have gone to help family thru this emergency
guess i lucked out when my K1 was denied and i ended up getting married and going spouse visa
BTW, if you are not returning to live in birth country, go ahead and get that police certificate now / saves time later