> reduced from 93 containers with 2GB of RAM to 33 containers, 30 (with 2GB of RAM) for the RoR routes and 3 (with 1GB of RAM) for the Elixir POST route.

Nice, that's tangible direct money-in-the-pocket results you can take an owner and make a case for a technology. Can talk about functional features, or advantage of actor based paradigm for concurrency but something tangible like that is hard to beat. They might answer with something like "I don't know anything about beams and elixirs but this looks good for the bottom line, let's adopt that".