Question nodes are for asking the user a question with multiple possible answers. These nodes are created with two default responses, "Yes" and "No", but any number of responses can be configured with any desired text.
Questions are useful for giving the user multiple alternatives and are the primary way a flow steers the user toward the information they need. For example, your flow might start with a question node asking what the user needs, with one of the responses being "I have a technical question". That response could then lead to another question node asking what the user's question is about, with your FAQ questions as responses. Each of those responses could lead to another question node with that FAQ category's questions as its responses.