Today, zeal often precedes biblical education. Whatever is meant by Missionary, oftentimes funding for fun trips and talking about the Gospel is called Mission work. Somebody is new to the faith and on fire wanting to talk about everything biblical. Often times missionary work is filled by first year students or groups of people wanting to visit a foreign land and talk about the Gospel. What ends up happening are excited youth going and nailing together something or cleaning up areas that manual labor needs to complete at the expense of the congregation.
In some denominations a biblical pattern is the process followed, a missionary goes out where the Gospel is scarce, and if the peoples respond the missionary returns and an evangelist goes out to build a church. Then the evangelist fills the church w/ the office of Pastor.
Evangelist is a general term used today, Luke was an Evangelist and Evangelist appear and disappear throughout history as necessary and called. For example, 10 blocks and a church exist on each of the 10 blocks. Why the need for another evangelist to build another church?