this is a fraction of a cost of a sans-amp, but gets a great variety of warm distortion and tones.

If you are designing a direct box that needs to replace a guitar amp altogether in your setup, you would expect something with this number of knobs and switches to be capable of purely clean tones (and a variety thereof).

A nice variety of amps as well as settings to choose from on the way to coming up with an original sound of your own.

Second, the GDI21 can be used in a home studio for recording directly into an interface (with either instrument cable or XLR), and it does offer a good variety of tonal options with the mod switches and knobs.