With Hep B 95% of people who are infected as adults clear it and don't go on to chronic Hep B
A major problem is that around the world, most of the people with chronic Hep B contracted it at birth or early childhood when their immune systems are weak and the clearance rate is <10%
With Hep C only 25% clear it and most go on to chronic Hep C
Hep C can be cured because it does not integrate itself into host cells. Hep B is a DNA virus and this DNA can form cccDNA - covalently closed circular DNA - in the nucleus of infected cells. What that means in english is that it can hide in a bullet proof dormant form.
Anybody who is HBV surface Antigen positive or has an HBV viral load should be treated with entecavir at the same time as DAAs or the the HBV will probably flare.
People with evidence of past infection who have cleared (negative surface antigen, positive core and surface antibodies) probably just need watching.