The meta description. This is of limited use, aside from simply discovering what pages do not have a meta description (and therefore require one).
General Usefulness:
★
Ease of Automation: ⚙⚙⚙⚙
⚠ Gotchas ⚠
Unless you are specifically doing an SEO audit or require a specific analysis of the description, this is of limited value unless the URLs / titles are not meaningful.