it is a sump setup just using buckets for the wet/dry/drip portion. Depending on the size of container/tank used, there is plenty of room for other equipment.
It will work for a reef setup, but not the ideal solution by a longshot.
wet/dry systems and many sump configurations are backwards.
the objective is to remove as much waste from the system as possible and get the most efficient benefit from the bacteria colonies.
As such putting the wet/dry/biological portion as the first part of the filtration scheme puts a greater burden on the bacterial colonies as they are the first "defense" so to speak. The idea behind wet/dry systems is to provide more oxygenation of the water for the bacteria to use so it doesn't deplete the overall oxygen saturation of the entire system which can happen if a system has a large bacterial population and inadequate oxygenation.
The best, most efficient configuration in my opinion is to have the water go through gross mechanical filtering first accomplished via filter socks or sponge, or similar media.
Next should be mechanical filtration of any dissolved organics via a protein skimmer as that is the only methodology that physically removes dissolved waste from the water circulation and should always be employed if for no other reason than that.
Third the water should go through chemical filtration if you choose to employ such, Carbon, Purigen, Chemi-Pure, etc.
Ideally the effluent from the skimmer should be channeled through the chemical portion. This will also prolong the life of the chemical filtration media as more waste is pulled out by the skimmer prior to reaching the chemical portion.
Finally should be the biological portion of the set-up. By putting bio last you are presenting less waste to the bacteria and thereby lessening the work load on it and it will better be able to handle any swings in parameters more readily than if the colony is already having to work at maximum.
Employing a wet/dry/drip setup at this stage is great because you get the oxygenation benefits of that scheme.
Again, this is my opinion, your mileage may vary.