The real power of variable axes is that it's not related to weight in the slighted. That's the most obvious use-case, but it's just a mechanism to control "which points in a glyph's outline go where based on what one or more variables are set to", so just using it to change weight is... kinda obvious and boring? Let's kick it up a notch:
Also Recursive (https://www.recursive.design) which has the usual weight and slant axis, with cursive alternates which can be toggled explicitly or used automatically when the slant is strong enough, but also a monospace axis (which allows for semi-monospace) and a "casual" axis which changes the whole character of the font.