If your cruise is 'all found' you won't need much daily cash, so taking a couple of hundred egyptian punds should be ample. If your cruise is taking you to locations there is usually a scrum of barrow-boys yelling for your trade, and many will accept euros. Be very careful in these situations about what you are buying and how much you are paying, and what change you should expect.
The biggest problem is finding enough small-denomination money as the low-value paper currency is in absolute tatters. Also said to be a source of tummy upsets - I won't elaborate but often men keep cash in their pants.