It doesn't matter how good a guitarist you are if nobody can hear you play. That's the eternal issue with electric guitars. With a solid body the strings are barely audible, and the signal that reaches the pickups is so weak that it can't overcome the resistance to drive a speaker. That's why you need an amp. A guitar amplifier takes that tiny signal and gives it a kick. It boosts it up to where it can not only drive a speaker, but even overdrive one. Without amplifiers it would be safe to say that the heart of rock and roll wouldn't be beating.