No, devs send files to Steam and Steam is releasing it. That is all and simple, also no time is taken. I think ED is lazy about this.
Also from Steam.
Automatic game updates
Hunting for patches and downloading from unorganized web sites is so twentieth-century. On Steam, your games stay up-to-date by themselves. No hassles.
http://store.steampowered.com/about/
I think ED is knowing this too. Because they are selling their game on that platform but they are not making auto updates for their products. That is really annoying, if you don't use Steam's features then don't sell your product on there. Sell the product only on your page. :)