The more widely known feature of Onion Services besides anonymity is the free and trustworthy end-to-end encryption they provide which is impossible to have under the Certificate Authority racket.
Another interesting property is they can serve as a drop-in Global Server Load Balancing and Layer 3 DDoS-resistance solution. In short a a free and libre CDN alternative to tyrants like Cloudflare. It can protect your site without compromising on principles like complete and unhindered access for your your users and readers.
This was recently brought up by network scaling engineer, Alec Muffett who contributed much code to make it possible to run heavy traffic Onion Sites.