We’re talking about many different possible situations here. Each with different consequences.
If you take a scene controller like the Enerwave or the GE, you can add it to a smartthings network as a simple on off device. Where none of the buttons work the way you want them to. But because it is owned by the same Z wave network, it could control scenes with other end Devices like Zwave light switches, only you can’t set up the scenes. So it just doesn’t work.
Now you have a whole bunch of different options.
A) set the scene controller up with a different primary controller like a GE remote or Vera, and when all the scenes are set up correctly, then exclude it from that primary controller and add it and its individual light switches to smartthings, and Smartthings will think it’s just an on off switch and will be out of sync as far as tile status, but you will be able to control the individual light switches either from smart things or from the scene controller. And if the smartthings cloud is unavailable, the scene controller should still work. This is what people tend to do with the GE handheld remote.
B) fool the scene controller into thinking it is a set of individual contact sensors. This is basically what the button controller smart app does. If you do that, then you can keep smartthings in sync with whatever you do on button controller, and they can both control the end devices.
It is not possible to do this with all devices, in particular it is not possible to do this with the ones that require controller replication. So you cannot do this with GE controller devices. But, and this is the difference, you can do it with the enerwave. It doesn’t always work perfectly but the basic idea works.
So now you have a button controller on the wall, smartthings knows what it does, and very important it can only talk to the end devices by sending a message to smartthings which then sends a message to the end device.
So if you choose this approach everything stays in synch as long as the smartthings cloud is available but if the smartthings cloud is not available, it doesn’t work At all with the V one hub.
It might work with the V 2 hub’s local processing, but only if the device type is an approved type. Which is why the minimote will work. But the Enerwave will not.
C) is a simple master switch and use Zwave association to let it control a simple accessories switch. This is not intended for scene controllers. This is basically used to set up a wireless three-way. All the devices have to be within one hop of each other. Which pretty much means the same room. But they can talk to each other without having to talk to the hub first.
It’s true that the smartthings hub status tiles will get out of sync if you use the switches on the wall. But other than that everything works really well. You can control the light from the switch. You can control it with schedules via the hub, if the smartthings cloud is unavailable the switch can talk to the other switch without going to the hub at all.
It doesn’t need special set up. It doesn’t need controller replication. It’s just one device talking to another device. This is a really common way to have a motion sensor control a light switch. To make this work, both zwave devices have to support “association.”
So you can see, here are three completely different ways of getting one and device to talk to another end device. Like a motion sensor to talk to a light switch. Or a master lightswitch to talk to an accessory light switch. Each way has its own pluses and minuses. And each Way works with a different subset of zwave devices.
So I think that’s where things have been getting confusing. People have been talking about the Enerwave sometimes as a scene controller, and sometimes as a button controller. They’ve been talking about the GE wall panel as a scene controller ( that’s the only thing it can be) . The GE handheld remote can be a primary controller or a scene controller (if set up by a primary controller other than SmartThings), but cannot be a button controller. The Aeon Minimote can be a primary controller or a secondary controller or a button controller. And a Cooper master switch can be associated with a Z wave accessory switch even though they are both just plain switches.
I don’t know if all that makes anything more or less confusing, but at least I hope it points out that we might be talking about the same device used in different ways in different threads.