CloudFlare serves as a guard between your webserver and the client. Every content the client receives got provided by your webserver and filtered by CloudFlare. This way, CloudFlare obfuscates email addresses by filtering them using a regex before delivering it to the client.
If your website contains the email
<a href="mailto:[email protected]">[email protected]</a>
CloudFlare will replace it with
The /cdn-cgi/ - folder, though it still points to the webserver, is only for CloudFlare which will automatically filter everything you submit, deobfuscating and returning the correct email address.
Of course this is not bulletproof (this is simply not possible) as a bot can continue on that URL or search for encoded email - patterns. This is a rare occurence and most of todays simple crawlers wont find your email.
You shouldnt rely on this approach - CF is already quite popular and it is easy to detect and deobfuscate those email addresses. Using your own, unique obfuscating techniques is more likely to be safe against intelligent harvesters as it is too much work adapting the crawler for every single obfuscation technique.