Not an expert on AWS, but as this seems something that you may need to share and that cannot be easily changed, considering it a secret is just snake oil.
I'd think of it as more a defence in depth measure. It's not a secret, but taking some common sense steps to not spray it all over the place could slow down an attacker, and a lot of the time just making yourself a slightly harder target than the next guy is enough that an attacker will go in search of softer targets.