Emblem Marth & Emblem Celica have a expierence buff at later bond levels as well. The 3H one is just more convient because it's a skill rather than having to use a certain weapon with Marth or a technique in the case of Celica. By the the time the pass drops in price they'll have added more chapters to it so your better off waiting anyway. Save those gold points in the meantime.
Once I got him I gave him the 3 houses emblem. Helped him get caught up real quick as it gives experience bonuses at a certain bond level.
I recruited Jean and he died the next fight. I had to replay the fight cause he seemed like a good healer to have in the group.