What is the benefit of an acoustic-electric?

Essentially, the earliest acoustic-electrics were simply acoustic guitars that had a standard magnetic pickup installed either in the soundhole or at the neck joint (as in the Gibson J-160E, popularized by the Beatles). Though these instruments could now be amplified, feedback was a constant problem, as was the compromised acoustic sound, as the pickups could not handle the complex high-frequency overtones produced by an acoustic.

In the late 1960s, all that changed when Ovation designed the piezoelectric bridge pickup. Rather than depending upon simple microphonics to increase volume, piezos amplified the actual vibrations of the guitar top and body and hence produced a more natural "acoustic tone." Over the years, many advances were made to help deliver a convincing acoustic guitar sound at concert hall volumes, with each manufacturer producing their own specific variation on what is now commonly called the "electro-acoustic guitar."

Most recently, Line 6, a company that built its reputation on complex "modeling" technology, unveiled the Variax, which could reproduce remarkably accurate models of popular electric and acoustic guitars. Their Variax Acoustic models are devoted to reproducing the most popular acoustic guitar sounds.

Given all that, the most important benefits of your modern acoustic-electric is the ability to play at concert hall levels and still retain the shimmering overtones of the acoustic, but without the feedback usually associated with high volume levels. Another benefit might be the ability to plug your guitar directly into your console, without the need for an expensive mic, not to mention a relatively noise-free environment to record it in.

Source: www.sweetwater.com