The ColorMunki Photo is a good device but it's often not supported by software such as the calibration tools needed to drive onboard LUT's in displays like the BenQ models. It has nothing to do with the ColorMunki itself or the monitor, really, it's all about whether the software in question supports the ColorMunki or not. You could always use the ColorMunki's own software to calibrate a new monitor just as you would do with any lower spec model, but that eliminates part of the benefit of buying a higher spec display that has additional hardware features.
However good the ColorMunki Photo is as a spectro unit, I would never recommend buying or not buying a system or monitor just because of the ColorMunki. That's putting the cart before the horse. Buy the system / monitor you need for its own features, and then adjust your support tools accordingly. You look at the monitor for hours every day, and process every image you work on based on what you see there. So I'd say optimize your choices for that decision.
If you create your own printer+paper profiles (or plan ever to do so), then the ColorMunki Photo remains a great tool for doing that, even if you need to acquire a separate colorimeter hardware device like an i1 Display Pro to calibrate your monitor. If you don't plan ever to do any printer profiling then perhaps sell the ColorMunki and switch to an i1 for use only with the display.