Not every person with autism is a savant. But many do have "splinter skills." For example, some people with autism are wonderful musicians, mathematicians, or artists. Others can design and create amazing structures, or read novels at the age of three.
In school, when Tom showed a surprising ability to do something that, in theory, should have been beyond his ability, I'd point it out to teachers and administrators. They'd say "yes, it's true - but it's really just a splinter skill." By this, they meant "yes, he can do it - but it doesn't mean anything because he doesn't relate it to the rest of his life."
My personal opinion is that dismissal of splinter skills is not only disrespectful - it's also hurtful.
How would a typical child and his parents feel if he were a terrific athlete but a struggling student, and they were told "oh, yes, he can play soccer like a pro, but it's really just a splinter skill." The implication would be that the athletics were irrelevant - cute, perhaps, but hardly worth encouraging. Instead, of course, typical children are highly supported as they show off all of their skills - and all of their skills are, generally speaking, celebrated to some degree.
People with autism are often lacking in many of the skills and abilities that are celebrated by the typical world. But most have something special to show off. For Tom, it's music. For other people it may be a knowledge of baseball stats, a talent for drawing, or an encyclopedic knowledge of Star Wars trivia.
None of these things are "just splinter skills" - they are talents. If "splinter skills" are pushed aside as junk, how is a person with autism to build a sense of worthiness or self-esteem? How is the world to see that person as talented, worthwhile, or interesting?
Of course, splinter skills can't stand on their own. But they are a foundation for building on. A talent for soccer, karate or dance can provide a typical child with a sense of belonging and prestige. A "splinter skill" can do the same for a child with autism. Just as importantly (and I'm speaking from experience here) - it can provide that child's parents with a clearer sense that their child, too, can shine.