After you've streamed your stored bytes into memory, you've got to do some work with them. Depending on what that work is, and how the file is laid out, you'll get a different amount of cache misses during that work.
I don't see what cache misses have to do with the storage formats
Ah, i see he's talking about a software resource cache, not the CPU's RAM cache... In that case, smaller more compact file formats would allow you to fit more files in your 'resource cache' at a time, whereas large bloated formats would waste memory and fill up your resource budget (requiring less resources to be loaded at once, requiring more streaming).