Why use datetime?

hour_format ="%H"
for avg, hour in sorted_swap[ :5 ]:
    hour =hour[ 1 ]
    hour = dt.datetime.strptime(hour, hour_format)
    hour =hour.strftime(`"%H"`)
    print(`"{ }: 00 { :.2f } average comments per post"`.format( hour, avg)

I seem to be getting an irregular result for my hour

04: 00 38.59 average comments per post
01:00 23.81 average comments per post
23:00 21.52 average comments per post
05: 00 16.80 average comments per post
00:00 16:01 average comments per post.

Although I figured a way to do it without using the datetime module, but just passing the hour str direct to my print. But I really want to know whats wrong if I do it this way.