The verse is Hebrew poetry. Hebrew poetry isn't like English poetry, relying on rhyme and meter. Instead Hebrew poetry relies on parallels and rhythm of ideas. This site already has an answer with the basics of Hebrew poetry. The second line of a couplet will restate the first in a slightly different manner. This verse has a triplet.
How is Sheshach taken!
and how is the praise of the whole earth surprised!
how is Babylon become an astonishment among the nations!
In the first line, we are told that Sheshach is taken. The second line balances "taken" with "surprised" and expands Sheshach with "the praise of the whole earth." The third line puts "Babylon" in parallel to "Sheshach" and "the praise of the whole earth." To keep the balance, "surprised" and "taken" are expanded to "become an astonishment among the nations."
So he uses both to keep from exact repetition.