Which explains why the Phoenicians developed a currency?

Answer 1

Without a currency, payment is made in goods (including precious metals) and services. A currency can save lugging wagonloads and shiploads of goods around unnecessarily. Trade was a principal activity for the Phoenician cities, so currency served them well.

Answer 2

They traded widely around the Mediterranean and beyond as well as at home. While exchange of good was effective, With the small ships of the time, and acting as intermediaries in carriage trade between countries, currency was a convenient way for minimising carriage of goods, particularly perishables and damageables, as well as being abl to be more explicit about the value of gods.