Of course...
I don't think I need to explain what the purpose is of a emergency fund...
Technically one can invest those funds with the current %4-5 interest, however for me, its the comfort of knowing I have the cash at hand.
When I see or hear questions about putting EF into anything but a cash equivalent, it's an indication that the person asking/commenting doesn't understand the concept. An EF, by definition, must be 100% safe (cannot lose money) and liquid (available at any time to use). If it happens to earn some interest to counter inflation/loss of purchasing power, that's nice. But never expect it to make money, it's all about safety and availability.