Why do they need Async templates? When a template renders it should be pure data and fully on the CPU. It seems Async templates would encourage a bad behavior of doing n+1 queries inside the HTML.
entries = Entry.objects.filter(
category="python"
).order_by("-created")[:10]
{% for entry in entries %}...
Async template rendering becomes necessary if you want the templates to be able to execute async SQL queries in this way.
Jinja has this feature already with the enable_async=True setting - I wrote a tiny bit about that in https://til.simonwillison.net/sqlite/related-content