Circumstances where you might see
<section>
used without a heading are typically found in web application/UI sections rather than in traditional document structures. In a document, it doesn't really make any sense to have a separate section of content without a heading to describe its contents. Such headings are useful for all readers, but particularly useful for users of assistive technologies like screen readers, and they are also good for SEO.
Consider however a secondary navigation mechanism. If the global navigation is already wrapped in a
<nav>
element, you could conceivably wrap a previous/next menu in a
<section>
:
<
section
>
<
a
href
=
"
#
"
>
Previous article
</
a
>
<
a
href
=
"
#
"
>
Next article
</
a
>
</
section
>
Or what about some kind of button bar for controlling your app? This might not necessarily want a heading, but it is still a distinct section of the document:
<
section
>
<
button
class
=
"
reply
"
>
Reply
</
button
>
<
button
class
=
"
reply-all
"
>
Reply to all
</
button
>
<
button
class
=
"
fwd
"
>
Forward
</
button
>
<
button
class
=
"
del
"
>
Delete
</
button
>
</
section
>
Result
Depending on the content, including a heading could also be good for SEO, so it is an option to consider.