For home and most offices, unshielded networking cables are fine, since there isn't that much electrical interference in those environments.
Shielded cables are more often used in industrial environment where cables pass thru zones with strong electrical fileds (motors, high-voltage cables and lighting, etc.). Shielded cables are much more expensive and the plugs takes much more time to do properly, leading to higher workers fees. Unless you do the plugs yourself, but you can't do that since you have no hands.