It's just like when the freshwater forum members tell others it's not good to keep goldfish with tropical fish. I really don't see a difference. Sure it can be done, yet that doesn't mean it should be or recommended that it should be done- which can be found on any decent internet site or knowledgeable LFS. Catalina gobies can live in temperatures in the 60s. It's not considered a warm-water/tropical fish. In fact, why shouldn't someone keep their tank at 70F, or less, degrees when they have catalina gobies? I'm sure it's because it's known that their tropical fish won't do well in lower climates and will most likely decrease their lifespan. So why do the opposite? The two temperature ranges hardly overlap.
Edited to add- reminds of of the mandarin dragonet goby. Why not add them to a (cycled) tank that's 1 week old? Hey, they may survive a little while. Why not keep our SW pH at 7.8? I feel these are similar comparisons.