> but I do wonder if BEAM is a bit of an overkill...

Why would it matter if something's overkill? If it's not much more work, and it runs on the systems you're targeting, it's better to start with something that's more reliable than you might strictly need than to start with something that you believe to be "proper kill", only to discover that you underestimated the amount of "kill" required. Retrofitting things like proper supervision and data/crash isolation can be a huge, huge pain in the ass.