The recommendations on markup for citation sources has changed significantly over time. Originally they said something like <blockquote>… <cite>…</cite></blockquote>, then they changed it to <blockquote>… <footer><cite>…</cite></footer></blockquote>, now they seem to be saying <figure><blockquote>…</blockquote><figcaption><cite>…</cite></figcaption></figure> Similarly what should be included in the text inside a <cite> element has changed over time.

Frankly, since the cite element has no implicit ARIA role and is normal flow and phrasing content, it’s roughly just another spelling of <i>. Don’t worry too much about its nominal semantics, they’ll probably tweak them again before long.