If you care about SEO (Search Engine Optimisation) you need to have Google Search Console.
It's Google telling you how your site, or sites are performing from a Google Search point of view.
Without Google Search Console you cannot say definitively how your site, or sites are performing.
There are some drawbacks for instance you won't get the power of synonyms. You cannot have multi keyword search - It's got be an exact search or a singular keyword search.