While Barkley is younger, I also think he has been over-used by the Eagles. After a long 17 game season, how much juice will he have in the playoffs? I could be wrong but my guess is that both Henry and Barkley wont be as impactful in the playoffs as they have been in the regular season.
Note that I had also said this (being over-used) about CMC and he has been injured quite frequently.