I didn't know about this, but as mentioned the basic idea has been around for a long time. Having said that, I had not previously run across the Wimberley MonoGimbal. I have the RRS MH-02 Pro tilt head on my RRS monopod, and while it's an excellent head you definitely cannot let go of the camera without locking down the head.
However, the design of the RRS tilt head does actually allow it to be used ('off-label' so to speak) as a monogimbal! The clamp can rotate through 360º on the head, the intent is to allow you to change the orientation to use the head with a camera plate instead of the normal lens foot. The rotation locks with a small knob (that's the upgrade with the MH-02 vs the -01, the ability to change orientation without a hex key). By dropping the tilt head to the end of the 180º range so the clamp is vertical and loosening the locking knob for clamp orientation, the head becomes a side-mount gimbal just like the Wimberley. Not sure I'll actually use it that way – the orientation lock knob is small (not convenient to lock the lens in an orientation when used sideways like that), and I'm not really sure it's robust enough to be used in a way the head was clearly not designed (I emailed RRS support to ask).
Regardless, I just ordered the Wimberley one. It's not too expensive (less than I paid for the RRS monopod head over a decade ago) and I like the elegance of the monogimbal solution for regular monopod use.