I was working on a basket case of a bike within the last couple of days, and it was equipped with a half link chain. I was reminded of one distinction of half link chains: all of them have full bushings. So they do have the same advantages and disadvantages as traditional bushing chains, just with less structural integrity due to their bent sideplates.
In a bushing type roller chain, which is the old/industrially standard kind, the inner sideplates are held together with small tubes (bushings), and the chain pins run inside these tubes. That gives a chain the maximum possible load bearing surface, which is good.
Such chains have been superseded by bushingless chains for most bicycle applications. These have inner sideplates that are formed with protuberances on them that serve the same function as tubular bushings. They have less load bearing area than traditional tube bushings, but they allow lubricant to flood the entire chain from wherever it's applied, and they allow the chain to flex sideways much more freely than traditional bushings do.
Bottom line is, bushing chains (like Kool Knight and other half link chains, along with industrial style roller chains) tend to have longer wear lives, but are trickier to lubricate, more likely to develop stiff links, and unsuitable for use with derailleurs or with poor chain alignment. You don't have to use half link chain to get full bushings, but that's one way to get them.