This is a common and of course interesting scenario.....
For the college coach, if he is telling the kid that he has a spot on the roster, then what he is doing is hoping that the kid develops into a pitcher who can help him win games in the future. For the coach, in this situation the program does not lose. If the kid doesn't develop, the team has not lost an investment.
For the kid, it can be looked at more than one way. Some kids are going to want to take advantage of this opportunity to play D-I and believe they are going to succeed, and some of them will succeed. That is a great situation, and can work into at least a little scholarship money later.
Other kids may want to go some place that they know they will get some quality innings in as a freshman....or where they think they will get some quality innings in as a freshman......
I know a non-pitcher who was presented this opportunity and jumped at the chance, and had about 100 plate appearances as a true freshman in a major D-I conference.....it sure seemed to be a great opporunity for him!
Bottom line, this is a tough scenario to predict......there is no wrong way to go.