Pages imported from the old wiki now appear in search results on LessWrong proper.
Pages imported from the old wiki benefit from all the features of new LessWrong such as hover-preview, subscriptions, commenting, and functioning as tags on posts.
Since LessWrong proper is an active site, hopefully, the wiki content continues to get updated.
People who land on the old wiki content will more easily find the rest of the awesome content/​activity/​community on LessWrong proper.
LessWrong proper becomes more like the proper LessWrong that it was meant to be, unlike the wiki which has far less activity than is proper for LessWrong proper.
I admit, I added the last bullet ;)