Theoretically a family could have dad wait in all the standby lines, and mom leaving with the kids because “bathroom emergency” each time they’re in a standby line. This gets the mom and kids maybe 30-60 minutes per ride depending on how much of the wait time is post merge to go do something with the kids sans dad in the park before they need to enter the LL again. So you have the family split, and no overall time saved unless the family is happy having dad miss out on every second attraction. Sure they can go eat, shop, etc., but again thats at the expense of dad. The winner here might be dad, depending on how he feels about family vacations lol.
There is very little incentive here to lie to game the system like with DAS even if you recruit a designated adult for waiting (which, we don’t know how easy it would be to have more than one adult plus children leave and return). You gain a little bit of line freedom for part of your party by spending more and more time apart the more time you “save”, and also investing more time by having to not only approach the attraction but actually make a show of queuing for a short amount of time. Unlike with DAS, the member(s) of your party who are doing the standby wait don’t get to participate in whatever you’re doing instead of waiting.
The real benefit is in not losing the spot in line and the wait already put in when someone in your party has to leave, which is exactly what it’s designed to do.