Do smokeless grills have an advantage over gas grills? On my quest to balcony charcoal grilling, without bothering my neighbours, I have researched many solutions.

I am now, pretty sure, that I can limit the smoke of the actual burning by using the right coal (like cocos coal) and lighting it the right way.

However, the main problem appears to be the fat on coal dripping, which results in a lot of smoke, no matter the coal type.

I have stumbled upon a "smokeless charcoal grill", which is specifically designed to be smokeless and it looks like this:



Source: https://www.youtube.com/watch?v=cmVlfXxh-x0

From what I can tell, this grill hides the coal and works by indirectly heating the food, preventing fat dripping on the coal.

While this makes sense, this also limits the flavors, which develop by the dripping.

I wonder if there is no fat on coal dripping, does this even have an advantage over using a gas or electric grill?

Would the food still get some smokey flavour from the coal? Or is this actually the same as gas or electric flavorwise?
Flavors don't develop by dripping onto the heat source

Flavor can enter a meat from smoke, but you want the flavor of hardwoods like hickory or apple. You do not want the flavor of burnt grease; I have never heard anyone describe burnt grease as a pleasant smell or taste. 

Therefore, you want the drippings to go somewhere that isn't the heat source. For some fatty foods this can be a problem, particularly 70/30 hamburgers or a pork shoulder. Many barbeque-ers will put a drip pan (a small tin-foil pan) into their grill to catch grease, keeping it away from the coals or the gas flame. Also, the drippings from some cooked meats can be re-used (like in a gravy), another reason for a drip pan.

I have never seen or used a smokeless charcoal grill. But, as long as the device works as promised and keeps the grease away from the flame, there should be no change in flavor of your finished foods.