You can at least easily Google "canary release" I suppose, in a way that's going to give a clear answer vs googling "PR" or "CI" (which will likely tell you PR means public relations and CI is the symbol for a "curie"/unit of radiation).

but it would be impossible to google FOMO...

Not sure what your point is, I'm defending not spelling out things that are easy to google. FOMO and "canary release" both are, while CI/PR, not so much. In principle if you were writing something for an audience that may or may not have heard of continuous integration or pull requests, at least spelling them out makes it easier for them to look up their meanings. I don't actually think it's a big deal either way, though it's surprising how often people use abbreviations and just (incorrectly) assume others know what they mean. If you're writing on any sort of interactive platform, being around to explain them if asked is probably sufficient though.