Levantine Spoken Arabic is a SPOKEN LANGUAGE, a dialect used in four countries that are called the Levant Countries or Al-Sham, Lebanon, Syria, Jordan and Palestine.
It's the closest to Standard Arabic and it's well understood in the whole Arab World.
We use it to communicate to each other. So even if you are working in a company or an organization that wants you to know Standard Arabic for official paper work, you will need to know Spoken Arabic for you to communicate to others in a lovely way.
Levantine is a mix of all the three countries' dialects!