Skye covered it above quite well! I took a bit of a gamble on the attenuator side as it’s hard to tell from videos how quiet something can get, but it’s really fucking impressive how that thing can bring the volume down to whisper levels and still feel like you’re playing out of a tube amp and without messing with the sound of the amp at all. It’s like the best master volume you can ever add to an amp, especially a non-master volume amp.
Like Skye said about using a load box/power amp, I did that all of once with one of my Class D amps and it just wasn’t the same experience, they’re fine for jamming in the living room or maybe some genres of lighter music/clean tones, but for playing in a metal band they’re shit until you drop $1500 on nearly 2000watts of class D power.