The 49ers have scored six of their nine rushing touchdowns with Boone on the field, according to Hank Gargiulo of ESPN Stats & Information. They have lined up Boone more at tight end (50 snaps) than at tackle (37 snaps). He's been used as a blocker either way.
Developing young players such as Boone is important for teams serious about upgrading their depth. The 49ers decided this past offseason to move on from veteran backups such as Barry Sims and Tony Wragge. That thinking has cleared the way for Boone to get an opportunity. The contract extension suggests the team thinks Boone has a future beyond this season.