As the others have said, they aren’t really better in any way. They’re just the only option some people have. I’ve heard it argued that there the scientific basis for claiming they are not as good at protecting against disease is somewhat lacking because there have been no clinical trials on the matter. This is true, but it is worth noting that the basis for the claim is that lambskin is porous, which is one of the problems condom manufacturers were trying to overcome when they came up with their latex solution. So just because there haven’t been any clinical trials on lambskin in particular, the problems they present have been recognized as problems for a long time.