The Adsense value is useful for filtering. It's simply a combination of traffic and CPC:
- High Traffic and High CPC = High Adsense Value
- Low Traffic and Low CPC = Low Adsense Value
However, if you have a ton of traffic, and the CPC is reasonable, you still get a high adsense value.
The best use is, if you add filters to other columns, eg.
- Top 10 Competition: <40
- Monthly Searches: >2000
... then sort by Adsense value descending - this way you get to the best keywords for Adsense.
Of course, in some case the keywords don't have many ads. But, what you could do is add the "Adwords Competition" value to the filtering too. If the Adwords Competition is >50, this means there are a lot of advertisers.