I'm a bit confused about the constant mention of option 3 in this article, because it seems to match none of the actual options from the original poll. The original poll offered three options:

Option 1: @nest. Requires either starting a nested selector with &, or prefixing it with @nest if the & should not be at the start.

Option 2: @nest restricted. Always requires starting with @nest.

Option 3: Additional brackets to group nested selectors.

The "option 3" mentioned in this article matches none of those. It's like option 3 without the defining characteristic of the brackets, or option 1 without the required nesting indicator (but now with the restriction that the selector needs to start with a symbol).

None of these options are particularly great. The new "option 3" looks cleanest, but the symbol requirement is going to trip people up.