Lmao, Egypt was quite poor and dependent on Rome at the time. Caesar was one of the most powerful people of his time, and never cared much for personal wealth anyway. Cleopatra was not single, she was married, and didn't give any wealth or political influence to Caesar. Same with Mark Antony, he was already quite powerful, and Egyptian forces constituted only a minor fraction of his allied armies. In fact, his alliance with Cleopatra might have caused his downfall since he wasted time with her instead of focusing on the war.