I am not a skimmer, and I certainly have not done a side-by-side comparison to back up my suspicions, but I must admit that I am a bit skeptical about the potential benefits of krausen-skimming. If the nasty bits that you are removing are going to end up in your finished beer, then it stands to reason that they must be dissolved in the beer. But it looks to me like this gunk is dispersed on top of the krausen and not actually dissolved. If that is the case, then I would expect it to fall out and not make it into the final beer. Especially so in a lager that gets extended cold-conditioning.