All cooktops I have worked with, both traditional coil electric and gas, simply drop into an appropriate sized cutout.
This cooktop requires a certain amount of space on all sides to keep the cooktop body from being too close to the counter. The border area of the cooktop overlaps the countertop (as with other types of cooktops) but without these spacers/brackets, the cooktop would either be loose within the cutout or, if the cutout were simply made smaller to fit the cooktop body, there would be a fire hazard. Or at least that's the way I understand the installation manual.
Why they couldn't have simply built the necessary extra space into the cooktop body is something only the manufacturer can answer (and likely won't answer, but that's a separate problem). My best guess is that a bean counter determined that the extra steel to make a larger cooktop body with empty space in it would cost more than providing a set of brackets/clips.
The catch is that these brackets need to attach to the counter. For a typical non-stone counter (Formica, other laminates, butcher block, etc.) simple screws work fine. Granite (and other stone) requires a different type of mounting kit for the brackets. All of which could be avoided with a slightly different design, but once you are committed to this cooktop you have to install it properly to avoid problems.
