Casting stuff has a ton of overhead cost and is very impractical for low volume production. EDM is expensive as all heck. For stuff that doesn't need to be made out of exotic material this is great.
For low volume production and prototyping this technology is great and cannot become mainstream soon enough. So what if it has to be finished. A casting or forging is the same way.
Forging costs a ton. The die has to be machined by (you guessed it!) a tool and die maker. Those guys are expensive. Once the die is made, however, bashing out the parts with it is fairly cheap per item.
Back when I worked in the aviation industry, sinking a die for a part cost a cool quarter million.
For low volume production and prototyping this technology is great and cannot become mainstream soon enough. So what if it has to be finished. A casting or forging is the same way.