After the first two days of the draft, teams will have selected (largely) 10 players. On the third day, they will select 30 more. Some of these won't be signed, but teams will make all of the selections. The purpose of many of these picks is to stock rosters of short-season teams. In the Cubs' case, this would be the Eugene Emeralds and Mesa Cubs. While many of them will be long-shots to get even close to playing a major-league game in Wrigley, they serve a purpose in the system, nonetheless.
After the first two days, people will look at the strays from a Top 200 list, and point out a few preps their team should seriously consider.