A lot of things don’t use syslog. For example, default configurations of Apache write logs directly without syslog. The benefit of this method is that it is general enough to work for most people without configuration changes, and I assume they could always add syslog support later.
Log.io assumes multiple nodes. If you want any kind of visit statistics in that scenario, you're already collecting the logs somehow. Unless you rolled out some homemade script for that purpose, you're probably using remote syslog anyways.
Or do you store your logs on a random server that request happened to hit / session was bound to?
