Yes, we all understand the difference between speed GR builds and pushing builds. The creators of these builds selected for the CRs simply do not. The vast majority of these builds have 1, 2, 3, 4, or 5 dead skills. They could easily get rid 1 of the skills that are doing nothing for you, and put a mobility skill in.
And this is totally irrelevant in a CR. 6 minutes is an arbitrary time, not a mandatory time as 15 min is for a normal GR. The point of the CR is to beat the builder, not to beat 6 minutes. If the algorithm selects a build that was done in 6 minutes with no mobility or 2 minutes with mobility, the challenge remains the same, beat the original time with the presented build.
As I have said in many other of these threads, the only real challenge to the CRs is trying to figure out what the person who made the build was thinking. Only once or twice have I had to run a CR a second time. Again, most these builds are clunky, incoherent, and unfun. CRs had soooooo much more potential, they were simply implemented in the laziest way possible.
What is clunky, incoherent, and unfun is having:
no mobility with 1-5 of the skills being dead
no defense skills with 1-5 of the skills being dead
no other utility skills with 1-5 of the skills being dead
having 1, 2, or 3 legendary powers in the cube that are also worn by the player
having 1, 2, or 3 legendary powers in the cube that are not used by the build
having 1-10 gear pieces with the wrong main stat