Air Spray and HVLP use fluid nozzles, not tips. These fluid nozzles are used to convey fluid and air to the air cap where all of the atomization takes place. These technologies are better suited to adhesives and materials containing aggregate such as metallics. Because of their infinite adjustability, these technologies are more versatile than any air-assist, Airmix or Airless system. They are recommended for texturing, staining, shading and glazing and you can use them on sealers and topcoats as well.
Diaphragm pumps are great for adhesives and stains.
Any gun can be efficient at low flow rates and with low viscosity materials. Even Kremlin concedes this at flow rates under 4 ounces per minute. I do a lot of cabinet finishing and refinishing, all on site, not in a booth or controlled environment. That is why I own airless equipment, a conversion HVLP, and for the last two years an Airmix. Every job is different and each may require one or more than one tool to complete it.