Sitemap - Include old URLs?

There is a feature in the sitemap stating that it will include old urls. I suppose this is what is looks like:

Code:

<loc>
http://www.domain.com/pokeri/701-20-04-pitkaestae-aikaa.html
</loc>
<priority>0.49</priority>
<lastmod>2008-04-23T18:47:42+00:00</lastmod>
<changefreq>yearly</changefreq>
</url>
−
    <url>
<loc>http://www.domain.com/showthread.php?t=701</loc>
<priority>0.49</priority>
<lastmod>2008-04-23T18:47:42+00:00</lastmod>
<changefreq>yearly</changefreq>
</url>

Those both are pointing to the same URL. Is there any sense in using this feature?

We have seen indications recently that this feature should be disabled. I do not feel that it is providing as much value for Google as it was intended.