Which is preferred--US dollars or EGP??
In local traders LE!
Only your visa, the odd ticket and usually hotels demand foreign currency.
Others will come on and say both are acceptable. Of course they are - If the choice is a $1 tip or nothing, guess the answer? And $1 is, in many cases far too much - e.g. the toilet attendant who hands you a single sheet of paper and then stands with his hand out. Are you going to give him 17LE?
See #10 here https://www.tripadvisor.co.uk/ShowTopic-g297…
The recipient, assuming he even has a bank account, cannot change $1 at the bank! He needs $5.
And, the solution is to then pester other guests to change the $ for him, but see #18 here https:/…95740127