Okay, #a11y peeps. Is it really a problem to have an <aside> inside of the <main> element? I have seen that assessment a couple of times, and I question if that’s correct.

The ARIA Spec says about role="complementary", which <aside> has:

A supporting section of the document, designed to be complementary to the main content at a similar level in the DOM hierarchy, but remains meaningful when separated from the main content.

Similar level feels like it permits nesting. Does it create any tangible downsides in practice?