It is, it is! SVG is DOM, with event handling on every node, with attempts to apply CSS rules. Canvas for non-interactive charts is just "draw once and forget". It is a sequence of moveTo + lineTo, then you have a bitmap and nothing else. Extremely basic graphics, modern JS engines will handle it in the blink of an eye.

I don't even mention the fact that article suggests to return each SVG sparkline in a separate request.

Ah, but Canvas does not rely on JS. You would update it using JS, yes. When you don’t update it, it’s just another image. Browsers are quite good at images.

In the end, I think it’s down to the complexity of the graph and the dimensions (in pixels, because images need memory, too).

Canvas is faster _because_ it relies on JS. It’s a much dumber and stateful API - the browser has to do much less work.

Especially if we're talking using "many hundreds or even thousands of them" on a page.