Yep, as PP explained, e-funds, like everything else in personal finance and life, need to be customized to your particular circumstances.
Look at your situation: income, job stability, cash flow needs, cash flow flexibility, risk tolerance, etc, and determine how best to meet those needs.
For some, credit cards or LOCs are a totally comfortable option for e-funds because they know that they can adjust spending/increase repayment rapidly if needed. For others, cash flow demands are high, fixed, and they don't have a lot of options if they need more money. Those people may be better off with actual cash available. Likewise some people aren't phased by their savings taking a hit while others are so desperate to leave their day jobs that the idea of a savings set back by selling at a bad time is just too stressful.
It's a very informative and useful exercise to analyse exactly where you stand in terms of cash flow and risk. It will really help you in terms of decision making in general.
There is no "one size fits all" when it comes to e-funds. As stressful as this is, is actually the best thing for you to realize because there are no rules out there that will keep you safe. There's just knowing your own personal situation and planning accordingly.
It's all on you to decide what you really need. As terrifying as that is, it's also for the best, because only you can really know what's best for YOU.