About 6-7 years ago I bought a machine that prepares single-shot cold brew with ultrasonic cavitation. I like my caffeine potent and chilled, so this has worked out extremely well for me.

When I have a guest that wants a hot coffee, I just pour the shot into a mug and top it up with hot water to their taste, which works great.

What this isn't is anything new. That doesn't make it bad, but it's not novel.