In most cases, even if there isn't a driver, a device should add to the hub. (I will put an asterisk here because there will be someone who will prove me wrong).
In my experience, the device will do one of a few things if it isn't a supported device.
- It will pair to the hub, and get the "device" driver which in and of itself doesn't make the device function.
- It will pair to the hub and pick a driver that pretty closely matches the device that isn't supported. It may or may not work exactly perfect. Often it does work right as one company can be the OEM for someone else's devices. Minoston and Eva Logic and Zooz are good examples of this.
- The device will pair and use a generic driver. It will typically function correctly, but you may lose some advances settings or occasionally a feature like power reporting.
These Minoston pair and work fine on Hubitat. Your issue is likely to be one of range, (not being close enough to the hub signal-wise to pair), or using an improper procedure to begin pairing (wrong or too slow button press etc.), or maybe you need to exclude the device before inclusion.