Hi, here is some (Berkleer) elaboration on the matter:
Connecting Your Guitar to the Computer
Some computer audio interfaces feature instrument inputs. If you have one of these, you’re ready
to go. An instrument input is usually labeled as such, whereas a dedicated guitar input might say
“Guitar In” or “Hi-Z (high impedance) In.” This high-impedance input is best suited to the guitar’s
characteristics, but a typical instrument input will do nearly as well.
Instrument inputs and especially hi-Z guitar inputs are designed to match the level and
impedance of a guitar signal, and therefore give you a stronger, cleaner signal, usually with a
wider frequency range.
as found in:
http://www.berkleemusic.com/assets/d...guitarists.pdf
All the best