From the video it appears a nice quality piece, perhaps it only cleans up the aesthetic of the headset upper bearing. Yet I've no experience with the system, I question it especially for the high price.

If one needs the threadless stem with all its advantages as mentioned, the simple threadless adapter for under $10 does the same. Plus you can raise and lower the height as the traditional quill stem.

This brings us to the term quill. The inni system really is a quill type and the video host even calls it such. But, once you set the bearing preload, its done. Now one still has to play with spacers to adjust bar height. Few like to keep the excess pipe protrusion, so its usually cut. Now you're left with a shorter vertical section and might not be as useful for another bike or if you later change your mind and wish to raise it.

Bearings. Would like to know more about them and of replacement. Tapered vs ball, type, end thrust preload is a study in itself. Definitely a critical part. Can completely change the handling and control of the bike.

Lastly, the argumentment one saves a few grams is moot.