As one poster in the Leica Camera Forums mentioned, “ Friends do not let friends use M11 'pixel binning’ ”.

Leica Marketing:

Stay flexible and choose from 60, 36 or 18 Megapixel resolution for DNG and JPG: The exclusively developed Full Frame BSI CMOS Sensor with Triple Resolution Technology in the M11 is a masterpiece of imaging technology.

What it's good for is smaller files at the cost of resolution and dynamic range. The claimed dynamic range increase is the same on attributed to downsizing any image, in that the noise floor changes and technically increases the dynamic range. However, here, you’re loosing resolution since the the downsizing isn’t binning pixels and it’s not downscaling post de-bayering. At least mathematically, the resolutions available don’t correspond as proper divisibles of the native 60.3 MP count. If anything, the smaller DNG file size should be around 15.075 MP. This way, the true colour per pixel can be calculated using data from the RGBG values combined into one final pixel value. 

If Leica could explain the resolution choices and how they compute these results then that would go a far way in understanding whats going on. Right now, I don’t understand why this feature exists outside of a marketing gimmick.

The L-DNG has an image width of 9528px. The M-DNG has 7416px and the S-DNG has 5272px. 

Large to Medium DNG resolution: Factor of 1.284789644
Large to Small DNG resolution: Factor of 1.807283763277693
Medium to Small DNG resolution: Factor of 1.406676783

I don't get it. I don’t see a pattern here that makes sense.

The M-DNG and S-DNG resolutions are files that are not demosaiced, so the downscaling happens at a raw data level. The results don’t benefit the user whatsoever except in creating smaller sized DNG files, but at a cost of detail, noise and dynamic range. I think this could be done better, and I’m hoping the output can be improved with firmware. 

As seen in the image at the top of the page, shot at ISO 25000, the downscaled 60MP image retains more detail with perceptively less noise since it's finer and smaller. The downscaling used here was a simple automatic photoshop downscale and not purposefully optimised in a way to benefit the comparison. Noise reduction was left at zero for both images. Besides the 89.4 MB vs the 27 MB file size benefit, I see only a sacrifice in image quality in using the alternative resolutions when compared to downscaled L-DNG files. 

My conclusion is that this Triple Resolution Technology is pure marketing and has no merit as a serious feature. The only benefit is a file size on average one third of the native resolution DNG file. With the prices of SD cards, this seems hardly worth it.