Starting this week,
create-volto-app is deprecated in favour of the new generator:
@plone/generator-volto: @plone/generator-volto - npm
Tested during the last months, it's based on the popular
Yeoman template system. It sports self aware update notice, and it can generate not only Volto projects but also Add-ons. It can also "upgrade" in-place projects, showing you the diffs between the old and new generated files.
There's a lot of room for the new generator to grow and new features to add, so feel free to contribute!