@tTxFlowers you make very good points. The best one you make is that how you choose to breed your birds is your prerogative.
SFH have crested and non-crested. There are genes that determine crest and are passed from crested and non-crested parents. Not all crested birds have vaulted skulls, and not all crested/crested breedings have all vaulted chicks. The gene which causes the vaulted skull may possibly be found in the same sequence as the crest, but may be expressed to a lesser degree. I'm not an expert by a long shot, so this is just a guess. In closed flocks or heavily crested/crested breeding programs the vaulted trait may become so predominant that it becomes common. Inbreeding isn't good for most species.
The crest itself, however, isn't a bad thing. The breed is what it is because it evolved to survive, and crests evolved in multiple breeds and the genes found on the sequence along with the crest can frequently be important to the breed's ability to thrive. A lot of people think you can breed one trait out of a bird and have no other impact, but then you have the great laying breeds being bred closer to SOP and giving up egg quality. You hear it from the tinted egg layers all the time... Marans and Langshans bred for body type give up egg size and color. You also hear from any overly bred species breeders that breeding to type eventually leads to other health issues. Look at show dogs.
The breeds that make up the SFH evolved to thrive with some crested and some non-crested birds. There may be genes within that sequence that causes the crest that are critical to the bird population, and breeding it out could potentially have a negative impact on the breed as much as breeding only crests to crests. I know several people who prefer non-crested who have reported reduced numbers on their hatches, as well. I prefer the crests, but I'm going to do my best to keep a healthy variety of genes within my flock, crested and non-crested, without breeding toward any specific type except health.