From T94223:

The Citoid extension in conjunction with the citoid service allows users of VisualEditor (a what-you-see-is-what-you-get way of editing wikis) to insert references automatically by inserting a link to a book, journal article, newspaper article, or other identifiers like DOI and PubMed IDs. However, it currently doesn't have the functionality to insert citation templates in wikitext.

There is at least one on-wiki JavaScript gadgets that already do this, i.e. https://en.wikipedia.org/wiki/User:Salix_alba/Citoid However, this relies on hard-coded wiki templates and won't work universally on other-language wikis. The reference toolbar suffers from the same problem of requiring hardcoded templates.

Per that task's closure, what was done there was adding "support to reftoolbar as a temporary measure until wikieditor has surface".
Per James' comment, that represents a valid solution only for a small bunch of wikis.