Sorry for my ignorance but G1GC is just perfectly tunable for all of my workloads (including low latency http request handling and high latency data crunching). What is the point of other GCs algos? Is there a specific workload that would benefit from it and it is not possible to use G1GC?

From the no-op garbage collector linked in the article they list a few reasons why you would want to use this garbage collector. See https://openjdk.java.net/jeps/318 under section motivation.

A no-op GC does indeed seem like an excellent idea for performance testing and memory pressure testing. Thanks for that link!

Thank you! These are indeed valid reasons to have something like EpsilonGC.