What does 301ing your own pages do?

The number 1 on my niche does this on his/her affiliated links. If I click on the affiliated link, it would ride me through a couple pages of internal pages before taking to the the final destination of the link which is the affiliated website. What does this gain?

Might be he is trying to hide affiliated link directly from google; This way he cannot get warnings in WMT saying (too many affiliated links).