For Fans of Flatpicking Guitar Magazine
Required? No. Crucial? Maybe, depends on you. Helpful? Probably. Recommended? Absolutely.
You can get online metronomes for free. You can get metronome apps for yoursmart phone for free. You can buy metronome devices for cheap. I recommend digital over mechanical.
A feature I like is a visual indicator of the beginning of a measure. For instance, the first beat of a measure flashes red and the other beats flash green.