Is this good for SEO

Some do say having a TCO on long-form content is good for SEO. I’m a proponent of simply providing good quality unique content is best for SEO.

Yes the direct benefit is that it creates links inside the URL that can be featured as rich results and extra links in SERPs.

Indirectly it also provides an index (table of contents) for visitors so if they find what they are looking for they will probably read it and increase the time they remain on your site.

So I would definetly say it does help SEO one way or another.