I have not been here long enough to see huge benefit from this, but have tried it twice.

There were two posts that I imported from my blog, both were over twelve months old. I only realized after the fact that they published on the same date I originally published them on my blog.

After they attracted a total of 1 view and 0 reads between them, I decided to delete the importanted posts and republish them. The numbers are not huge, but they both have 4 views and 2 reads each now after a day or two so definitely a positive move.