A local Egyptian SIM card is inexpensive, widely available, and straightforward to set up — kiosks for the major carriers are right in the arrivals area at Cairo International Airport, and staff there generally handle the setup for you with your passport.
Why it's worth considering
It's a reasonable option for travelers who want reliable connectivity beyond hotel or ship Wi-Fi (see Is Wi-Fi Available on Nile Cruise Ships? for how patchy that can be), especially for navigation, messaging family, or staying reachable during the day while out on excursions.
International roaming through your home provider is the simpler alternative if you'd rather not deal with a second SIM, though it's typically more expensive for heavy data use over a week or two — worth comparing your provider's roaming rates against a local SIM's cost before you decide.