Text from a paragraph style used in a variable does not carry any character styling.

Define a variable using the text of a specific paragraph style. Add character styles to the text (or use a GREP style) and when the text is
pulled" by the variable the character style is not reflected.

Often this is used for running headers and footers. Example: if the registered trademark symbol is added to the text, it is regular case in the variable.

This also really screws up the ToC when the paragraph style is used in a ToC