Can someone point me to where the benefits of the mini-blockchain scheme are clearly stated in contrast to proposed blockchain pruning?

Also, I'm trying to run the webrpc client and I'm getting the error: Fatal error: Call to undefined function curl_init() in /var/www/html/xcn/lib/rpcclient.lib.php on line 130 . I've started cryptonited with -server and ensure that the username and password are the same as what was entered in the client install. Any idea of where I'm going wrong?