But in general it's the only way to understand who's linking to you. Sure, not essential, but useful to see in general, especially when search engines could send it and you could see what keywords people used to find your site. If it were gone, as it is in many cases now due to https, people will adjust.
That's not exactly true. Referrer is only hidden if it's explicitly asked by using a meta tag:
<meta name="referrer" content="no-referrer" />
Or by using Referrer-Policy:
Referrer-Policy: no-referrer
The default behavior is no-referrer-when-downgrade. This means that referrers from https to http are hidden. But https > https is still visible. And with https adaption reaching saturation, referer headers are usually still sent.
