Emergency doesn't knock on the door, it happens when you least expect it. that's why you need to be prepared. To be honest, there are things we shouldn't joke with, and emergency funds are one of them. Using funds meant for emergencies is unacceptable, even if it means taking a loan. I don't even like putting it in bank because sometimes the bank might disappoint you when you need your funds. I think the best way to keep an emergency fund safe and secure is by keeping it in cash, so In case it happens, you can access it and solve your emergency.
You just raise a very important point about the emergency funds, when emergency is about to happen, it doesn't give sign or warning before it happen, that is why emergency funds is not a optional it's necessary, anything can happen at anytime, things that you don't even expect, but once you prepare yourself, having emergency funds aside, it can help or support you whenever the issue raise up, so my point is joking with emergency funds is dangerous, any investment we put hands to do, emergency funds should be untouchable. Whenever the emergency funds is safe, that will prevent you from unnecessary panic when there's any issues.