The Fusion’s internal amp and speakers are surprisingly loud; 95 dB at 1 meter, much louder than an acoustic guitar which is 80 - 85 dB.  It can provide enough volume for a cafe or small bar gig, or for street busking on a quieter street.
If you need more volume for a bigger gig or band practice, simply plug the Fusion into a regular guitar amp or PA using a standard guitar cable.