For me, a table of contents plugin makes sense for an FAQ or encyclopedia article that has 30 one- to two-word headings that are sorted alphabetically. Otherwise, the teaser must tell me what the article is about. I think it would be useful if the table of contents were placed under the menu bar as a separate standing bar (only opened when needed) If I only had a maximum of 3 word headings, it would make sense.
With longer headings, the table of contents just annoys me. The table of taiwan whatsapp contents can also be off-putting, along the lines of: “It just doesn’t get to the point.” The table of contents tells me in advance that I have to read a lot, so I’d rather skip it straight away. I think a table of contents can be useful for classic categories like: Nike Shoes > Men > Men's Tennis > Men's Tennis Red .
BUT most of the time a page only ranks at the top for one or two of these longtails. I think users would rather scroll down to the red shoe when there are attractive pictures than read through the 20 color variations. With good text contributions like on SIN, I look forward to the next headline. If I read the headlines beforehand, then the excitement is gone and I think: “I already know all that anyway.