Google Search Console is a program that allows users to monitor their website, and get information on how much of a presence their website is in google search results.
Updated and Legacy Benefits
Google Search Console currently has a set of updated reports/tools and a set of legacy reports/tools. One of the more helpful updated tools is the performance report. This tool is very useful for site owners because it allows you to see data like how many people have click on your website through google and your average position on the search page. One of the more important legacy tools is crawl stats. This tool shows you if your website is slowing down due to requests. Without this tool, you might not realize your website is running slower than usual. Crawl rate settings is also offered as a legacy tool. So if you see that your website is being bombarded with requests you can use this tool to lower the amount of requests coming to your website.
Why Keep the Old?
One reason for Google keeping their legacy tools around might be because users that used these tools frequently before google updated did not want these reports to go away. so Google kept them around to compromise with users.