Ultimately seed points really only have one use - 'buying' extra upload credit to improve your ratio.
Click on Bonus at the top to see the going rates.
If you have seed points you can give them to uploaders on a torrent page to say thanks. They can then use them to buy credit although you won't know if the uploader needs them.
If you find that your own ratio is looking unhealthy you can use your seed points to boost your upload (minimum 100 points)