Yes of course, i don't see any reasons wrong with an investors keeping his emergency fund in the bank, we should not be more concerned about were the emergency fund should be kept, what really matters is to make should you have reserves funds which you tag as an emergency fund and it is also bad to keep your emergency fund within your reach, because as the name implies emergency fund, it most serve its purpose for you as an investors, it is a very interesting discussion I'm seeing here, i know that it will help allot of newbies that doesn't have knowledge on how important emergency fund is to every investors .
So how exactly is it meant to serve its purpose if it's not within your reach? Let's assume you keep your emergency fund completely out of your reach and then boom, a emergency occurs at that very instance that requires you to dip into your emergency fund, but your emergency funds isn't currently in your reach and would take sometime for you to access it, what exactly are you going to do. An emergency fund should be kept in a liquid form, being made available and easily accessible to you whenever you need it, else yu might just end up going ahead to use your investment to sort an emergency, thereby defeating the purpose of the emergency fund.
For me it doesn’t really matter how you keep your emergency funds but no matter the decision you make it should be kept in a place that is very accessible. It called emergency funds because it always need at an emergency time, so when it is in need, how accessible the funds is at that time is what really matters. If you decided to keep in naira or not, in bank or not, just make sure it not something that will be difficult to access when needed.
We have seen many people lose a lot of things, even human life just because they couldn’t have access to money, so it is very advisable to make your emergency funds very accessible.