This question already has an answer here:
From what I understand after reading Google's Controlling Crawling and Indexing:
- The purpose of robots.txt file is to disallow crawling of some URLs, but those can still be indexed (and appear in search results) if they are linked from crawlable pages
- To prevent a page from being indexed I need to make it crawlable and add the noindex meta tag in its head
So, why would I setup a robots.txt file if, in the end, it has no impact on whether pages appear in search results or not?