I want to give them props for doing this. Some of the successful projects I've worked on talked with people, outside of issue queues and slack, to understand their needs. It worked out well in crafting useful solutions.
They say on their website what they believe they add, but unfortunately right now it still isn't in a stage to replace GnuPG. I will say trying to automate GnuPG key management sucks right now, so at least Sequoia might be able to get the DevOps crowd.
You could start by, you know, Googling the source code for GPGME. Or, for that matter, reading the GPGME documentation. This isn't an eldritch secret of how GPGME works.