Not only will Hartman be paid more, he's less useful.
He's not a 3RW I want on my team, and he's not a good defensive player on the 4th line.
Pitlick is a good fill-in who will help the PK, and who could center a checking line if they move Laughton up to 3LW (and Lindblom or Giroux to RW). He's got more value to the Flyers this year than Hartman, as long as he stays healthy this fall (by spring someone will be pushing for his job from LHV).
It not only saves cap room, it avoids a multi-year deal for Hartman blocking better prospects at LHV.
Hartman or a late 3rd (still haven't seen a credible report of a 2nd for Simmonds), meh either way.