What value do I get by integrating IBM Performance Management and IBM Control Desk and/or IBM Predictive Insights?

Predictive Insights makes a forecast based on the data from Performance Management. So you can plan for additional capacity in advance and avoid surprise failures. 
Integration with Control Desk helps speed things up because now tickets can be opened (on your IT team) automatically whenever the Performance Management data goes out of bounds. No more waiting for somebody to analyse the issue and then open a ticket.

Appreciate it, thanks for providing.