Non-doctrinal open-topped troop transports that also act as reinforcement points. Their armies lack infantry mobility in general.
Fair point. I would just like to say that using transports to ferry your troops from the base to the frontline is something I virtually never see, transporting stuff is much more often used to get behind MGs, for instance. This is probably due to micro requirements and how cumbersome loading into transports is.
Also, using halftracks to reinforce on the front requires soft retreating, which is not always possible, is micro intensive and in the end probably ends up taking the unit off the frontlines longer than actually retreating to FRP does (especially considering FRPs are usually paired with a healing option, which for EFA is more complex to achieve).
In contrast, forward retreat points usually require a smaller investment (that is, if they don't come free with teching outright as in the case of US), there is no micro involved, and they work for any number of squads. Keeping your halftrack alive and near the frontlines is also additional micro tax in itself.
Keep in mind that soft retreating not only takes longer than hard retreating and is more micro intensive, but also your troops are more vulnerable because they miss out on the retreat modifiers of speed and damage resistance, which means they will a) spend more time under enemy fire, b) this time spent will happen without protective modifiers, or c) they will have to soft retreat earlier than they would hard retreat.
So in conclusion, I do not believe these transports begin to even remotely make up for forward retreat points. It is however one of faction advantages, certainly, in the same way Conscript merge and Ostheer bunkers are. Lack of on-the-field reinforcement for WFA factions is definitely something that should be considered in the course of balancing the game.