I wouldn’t dare make comments on what’s more or less usable in an HN thread since everyone here is such an expert on these things.

Toggles came along with iOS when the UI was skeumorphic ca. 2008. Don’t know whether it has to do with tech, but that’s when we first got those.

As far as actual evidence, I do UX testing of a touchscreen/cursor application and we have both scattered throughout. I haven’t ever seen anyone have any difficulty understanding, using or differentiating between either. In our results this simply isn’t a problem with investigating.

Checkboxes are slightly problematic in touch UIs because they are generally scaled to a similar size as text and small enough that they are occluded by a fingertip. Sliders leak information about their state while you touch them.

Checkboxes can be just as usable but they're often smaller and often more tightly spaced, which can be a pain to navigate on a touchscreen.

I'm not saying that's a good reason, but it is a reason besides being newer.