Successful deployment of student technical support requires recognition of the specialized training needs of these workers and planning to address those needs. Yes, these students may have started using computers when they were five, and perhaps they know more about some aspects of computing than some professionals, but these same students may lack the interpersonal skills or just plain common sense to work well in the professional environment. They need careful coaching on how to interact with faculty, for example, which is rather different than interacting with their peers. They also must be able to interact with their less experienced peers in a gentle and productive manner. Cultivating such skills usually takes some time.
Turnover is one of the greatest drawbacks to student assistants.
It seems that as soon as you get student assistants reliably competent, they are gone, and the training cycle must begin again. To minimize professional staff time in training, it is imperative to be able to hire multiple students in order to keep some senior assistants who can train the incoming newbies. No matter the job, most students will make mistakes and part of training those students is correcting the mistakes. This can be a miserable problem. Once you've spent a great deal of time advertising the position, interviewing, and training the incumbent, you have a vested interest in making the student a success.