This split provides us many advantages, but I will list a few:

1. Since condenser (the software that powers steemit.com) will soon not have a need to handle high value keys it will be much easier to add new features to the social media side (steemit.com) without as much security review. This means it will also be much easier to merge in desired community contributions.
2. It is more cost effective and efficient.
3. It is an excellent opportunity for education regarding the Steem blockchain's unique hierarchal key system which helps to keep user's funds safe and secure.