registering in a queue, and reserving a charger
These are interesting questions.
I noticed on the kerbside charging thread that it is possible to reserve some of these chargers.
Regardless, I'm not sure how I feel about the ability to reserve a DCFC. Depending upon how it's implemented, I guess I can see pros and cons.
Pro: if everyone gets on the "reservation" game on a busy holiday weekend, for example, at least you would find out where you stand, or be able to change your plans ahead. For example, you plan to charge in Betoota at lunchtime on Saturday and eat lunch in the hotel. You pull out your Evie app, and the 16-stall Betoota charging station is already fully reserved until 4pm. No problem, you delay your travel, book the charger for 6pm and eat dinner in the hotel instead. At least you knew ahead of time and were able to change your plans.
Con: if not everyone is on the "reservation" game on a busy holiday weekend, you turn up in Betoota at lunchtime to find the DCFC full. No worries, you're used to grabbing a tinnie from the hotel and waiting in line. Still get charged up after a bit of a wait. But now, all these out-of-towners have reserved the charger, and keep turning up, one-by-one and queue-jumping you. By the time you manage to get a charge you are in no fit state to drive. Whatever happened to "wait in line in the order you arrive, like we've been charging in Betoota for centuries?" That's the civilised way to do it...
As for "registering in a queue", I can only guess they mean that when you arrive at a full DCFC, you register your position in the queue in the app, which presumably will enforce that queue if someone tries to physically queue-jump you. I recognise that the physical layout of DCFC's does not always provide for orderly queueing of vehicles in a line, and you might not want to wait in your vehicle anyway. So you arrive in Betoota, and oh no, the DCFC is busy again! I knew they needed more than 16 bays. No matter, register in the queue, go in and order lunch, and the app will tell you when the charger is available. All you have to do is put your fork down, duck out and move the car and plug it in. Maybe you have 5 minutes to plug in or lose the spot or something. Bit hard if someone blocks you though - hmm that sneaky loophole would have to be solved. But it does sound like a better system than physical queueing, if well implemented.
Pro: A major pro would be that this might be the only way the Evie app could work out how many people are queueing, information which could then be made available in real time in the app for those enroute and may be planning to charge there (in the way only Tesla can currently, and even then only at Tesla-Only Superchargers - unfortunately, Tesla can no longer tell who's queueing at Non-Tesla-Only Superchargers).
Con: Oh no, are we forcing people to use an app again? I only have my RFID card, my phone's dead.