Brit makes the common-sense point that Frank Sinatra was the greatest jazz singer of all time, and some people have the audacity to disagree. What Sinatra could do better than any other singer is come up with a phrasing that is both unexpected -- almost unduplicable, even if you've heard Sinatra -- and serves both the lyric and melody perfectly.
The best example of this comes in Frank's arrangement of Cole Porter's "I Get A Kick Out Of You," which is almost unsingable for those of us who have heard Frank but aren't Frank. Unfortunately, I couldn't find Frank's best version on YouTube, but this bowdlerized version (apparently, it wouldn't do to admit that someone might love cocaine) isn't bad:
Frank's phrasing makes the "bore me terrif/ically too" lyric. Try to sing along and you'll never quite make it.
On the other hand, in the "Love and Marriage" rendition linked by Brit, Frank does nothing with the singsong melody, other than keep singing it as steady as a metronome. Only at the end, with the second repetition of "Dad was told ... by Mother" does he have any fun with the phrasing at all.