Why these three
They share a failure mode: each one breaks silently. An expired certificate turns away every visitor at once, with no warning beforehand. A missing meta description costs you the line of text under your search result, and nothing anywhere tells you it is missing. A page with no Open Graph tags looks broken every time somebody shares it, and you only find out if someone mentions it.
Each tool is also available as an API for doing the same thing across a whole site on a schedule, which is the version worth paying for. The tools themselves are free and give you the complete result — a partial answer would only make them look weak.