Well, according to the doc, you can only render plain HTML.
The contents of the span will be replaced with the value of the rawHtml property, interpreted as plain HTML - data bindings are ignored. Note that you cannot use v-html to compose template partials, because Vue is not a string-based templating engine. Instead, components are preferred as the fundamental unit for UI reuse and composition.
If for some reason you have to output something dynamically based on a variable, why don't you place your element or component in the template from the get go and update its visibility/classes/props based on the dynamic variable?