You pretty much have it right. Think of a normal dosing pump, lets say you're dosing alkalinity, occasionally your going to get that half drop at the end of the tube that refuses to drop into the tank. Eventually that alkalinity dries and crusts over the outlet. When the Versa parks, it pulls that half drop back in keeping the tip clean longer and keeps that fluid for the next dosing event.
What if you're micro dosing a trace element that requires a precise 6 ml/day and you have that spread out to dose every hour (0.25ml every hour). Lets say say that 12 of those 24 dosing periods half a drop gets stuck at the tip and evaporates, that means it doesn't get added to the tank. You're not really dosing 6ml are you? Today you had 12 half drops evaporate, tomorrow you get lucky and only 6 half drops evaporate, the next day 18....etc. Your dosing isn't consistent, pulling it back in aids in complete accuracy. Keep in mind that these are simply scenarios to further explain the reasoning and purpose for the function.
In terms of added wear, of course the pump has to run longer to park, any wear that might be added is extremely insignificant compared to the benefits of having that feature. There's also a benefit to having the rollers pinch the tube in the same place every time which extends the life of the tube.