Hubitat groups--if you mean from the Groups and Scenes app--are, for the most part, not anything special; they're mostly the hub doing a bit of work for you so that you can use one "proxy" device to manipulate the member devices (on/off, level, color, etc., depending on the capabilities--though the group will show you all regardless) and optionally view something about their states (that's what the options you can configure like having the group device show on/off based on the member devices do). This makes it easier to, for example, use devices in apps/rules without needing to specify the same thing for a bunch of individual devices or to change out the member devices without changing the devices in every app, etc.. For Z-Wave and LAN devices, that's about it. For Zigbee devices, there is the option to enable Zigbee group messaging, which can help by sending one command once that all group devices (if all Zigbee, otherwise of course just the Zigbee ones) should hear instead of having to send the same command to each device one-by-one. That's the only advantage from a technical perspective.
So...basically, groups can be nice, but they are probably not what you're looking for. What it does sound like you're looking for is Z-Wave Association. I really don't think a lot of people on Hubitat use this (most new-ish devices where you'd want to use this also support Z-Wave Central Scenes, usually interpreted as button events by the driver on the hub, and it's pretty easy to assign some automation using the hub to whatever devices you ultimately want--which it sounds like you're doing and aren't happy with its performance, but whether that's the fact that the hub is acting as a middleman or just the way the devices themselves work, it sounds like none of us know). In fact, Hubitat doesn't have anything built-in for using Z-Wave association groups. There is at least one third-party utility that was written for this purpose: Hubitat/Apps/z-waveat at master · InovelliUSA/Hubitat · GitHub (technically written with the manufacturer's, Inovelli's, own devices in mind, but it should work with other devices, too). The unofficial (not built-in but available) Basic Z-Wave Tool from Hubitat may also be helpful if you want to set a specific parameter to a specific value (you will obviously need the devices' manuals to know what to do with that).
Also, if you need a lot of these and aren't set on the Wallmote, a lot of people like Lutron Pico Remotes for control of lights or pretty much anything that Hubitat can control (like the Wallmote, it's just a button device you can use to do literally anything with Hubitat). You'll need the Lutron Smart Bridge Pro to make them work with Hubitat, which is a bit of a steep investment for just a few button devices, but since you're considering the Aeon products, it's really only the cost of about two of those. Then the Pico devices themselves are usually pretty cheap--the white 5-button ("3 button with raise/lower" in Lutron terms) Pico can often be found for under $13. So for the cost of just three Wallmotes, you could get the Smart Bridge Pro plus the same number of Picos, then the total cost per device only goes down in favor of the Picos from there. These do support the ability to "associate" themselves directly to Lutron switches without putting Hubitat in the middle (sort of like you can with Z-Wave), but I've never done that--a lot of devices I automate are not Lutron, and the performance even with Hubitat in the middle is still so good that I've never been tempted to.
And unlike the Aeon, these will fit in a standard US decorator plate, so you might be able to convince other people that they are actual light switches, and they should be fairly intuitive to use. 
The battery life claims (10 years) are also impressive. I haven't had any for that long yet but don't doubt that I'll probably get somewhere close (Lutron's claims are usually pretty conservative), and it's likely to be a lot better than a 500-series Z-Wave device in any case. Lots of people on the forum use and love Picos. I resisted for a while (I tried a lot of other devices first--Hue Dimmer, Eria Remote, and whatever I could do with the 30-second battery life on my super-old Aeon Minimotes) but eventually caved. I'm a fan now, too.
Just another option to consider since you said you weren't totally attached. But I'd try experimenting with association first since if you don't totally hate the Wallmote since you already have it.
