air driven skimmers are not inferior to venturi they just require more maintenance. Air driven skimmer use wooden airstones that break up the air into smaller finer bubbles then venturi skimmer can In this way they are superior. This is why they make a big deal out of the needle wheel design because the impeller breaks up the air bubbles to be even finer some say as fine as the wooden airstones.
another advantage of an airdriven skimmer is contact time.
the following is taken from a website:
Air-Driven skimmers were the first models to enter the hobby in co-current (air flowing with the direction of feed water: a poor design for aquariums) and counter-current styles (air flowing against the direction of feed water: a better design for aquariums). They may be internal or external in nature, and gravity fed or pump fed. These simple units use air bubbles produced by strong air pumps and generally wooden air stones. Even though they are called air-driven, some come with a water pump that feeds the skimmer raw water to be processed. Most modern incarnations of this style are a counter-current design. Essentially, this means that water enters near the top of the skimmer and exits from the bottom while tiny air bubbles are injected near the bottom and work their way to the top with resistance from the water flow which increases contact time and strips proteins from the raw water.
Counter-current air-driven protein skimmers can be very efficient at removing significant amounts of quality skimmate. They have lost favor with some hobbyists because of their dependency on sometimes frequent maintenance and adjustments. Wood air stones decay over time, which results in increased backpressure, decreased bubble production, and less skimmate extracted. I recommend the replacement of wood air stones monthly or better to maintain optimum performance. Another drawback to air-driven skimmers is the need for an air pump. They can be noisy and generally use a rubber diaphragm to pump the air. These diaphragms degrade if not rupture in time. While they last considerably longer than wood air stones, at a year or more for most, this is another aspect of maintenance and upkeep to consider.