wern101 The iRig (or similar interface) opens Garageband up to guitarists. It's probably the cheapest way to get the most out GB. All my challenge submissions have been recorded using iRig and GB.
A-A-A-A-A-N-D, making it even more interesting...... I got my iRig off Aliexpress for around $5 four years ago - so it clearly is not the original. (At the time I genuinely did'nt know there is a difference.) Nevertheless, it performs perfectly every time.
BTW, a "normal" audio interface like Scarlett focusrite, Roland Rubix, etc also works fine with the right adapters.