Onionbalance is one of the standard ways onion service administrators can load balance onion services, but it didn't work for v3 onions. Until now.
If the Tor Project, the Tor network, and Tor Browser were to disappear, what would happen? Not only would millions of global, daily users lose access to Tor’s software, but the diverse ecosystem of privacy, security, and anti-censorship applications that rely on the Tor network would cease to function.
Fixing the guard discovery problem in Tor itself is an immense project -- primarily because it involves many trade-offs between performance and scalability versus path security, which makes it very hard to pick good defaults for every onion service. Because of this, we have created an add-on that can be used in conjunction with a Tor onion service server or a Tor client that accesses Tor onion services.
Many PI partners work in challenging environments, with massive state surveillance and/or ongoing censorship programmes. Giving them an ability to securely browse the web (both clear and onion) in a way which allows them to evade dragnet surveillance also allows them to conduct investigations securely.