Every once in a while, the two or three USB ports your laptop affords you just aren't enough. The Infinite USB concept makes do with what you have by cozily stacking your USB devices right on top of one another.
If a regular USB hub is like an apartment building, each device getting its own private port, then this concept is like a USB plug slumber party. Everyone's all up close and personal, but slumber parties are spunky and novel and FUN, so it's OK.
Sometimes, though, sleepovers can get annoying: you forgot your toothbrush; your best friend snores; you're allergic to their cat; whatever. In this case, the annoyance is that some serious planning is required for the Infinite USB system to be effective. Unplugging the first USB device means unplugging all the ones that are piggybacking on it, which could cause some frustration if you're in the middle of loading your MP3 player or backing up your hard drive.