Actually, they'll be very helpful--most especially there's no icon that says "database" in the way libraries use it, and the "official" database icon is pretty damn obscure anyway. Toby had to tell me it was stacked drive platters, as I always thought it looked like an oil barrel! It'll always be next to the word "Databases" and never by itself, though.

Including icons for various categories is more an aid to people scanning the page quickly than anything else, so there's a bit of redundancy designed in.