I'm simply saying that shocks and pgrens serve the same functions. I'm saying that I don't see how pgrens are more flexible. Shocks need to get close. Pgrens still need to be at least midrange. Even cons will beat pgrens at max range. However shocks can always afford to charge due to having cheap smoke and simply being a beefier, armored squad.
Pgrens don't have to kiss to the enemy to work. If shocks are facing fussies or ass grens they have 1 place they need to be- on top of them no ifs ands or buts pgrens can afford to stock in cover for some engagements. If they are fighting Tommy's they CAN close for an advantage if the cover is there and if they are fighting sappers they can sit and shoot on approach. That's their flexibility not to mention the ability to transition to emergency AT. Shocks are great at 1 thing pgrens are good at a couple. All I'm saying. Plus there is not a single doctrine with a tiger or elefant or command tank or Pak or arty or railway or OPel blitz trucks ect that does not have pgrens. The availability alone is a huge boon as they allow the flexibility to pick what you want without losing out