As well as precautionary and safety issues you may wish to use the CC (constant current) capability specifically for circuit operation purposes, or even CC and CC together.
The following examples are not 'contrived' - I regularly use a bench power supply in the manner and applications described below.
A PV (photovoltaic) panel aka solar panel when operated in a typical illumination range has an output that approximates a constant current source up to a certain voltage and the current capability then falls off rapidly as voltage increases (or voltage drops as load current increases). This characteristic can be simulated for test purposes by a power supply set to a voltage of panel Voc and a current limit of Isc. The actual panel Vout will droop slightly across its operating range and this can be simulated by a series resistor. The end result allows reasonably good simulation for may test purposes.
LEDs should ideally be driven by a constant current source. When testing LED based equipment a power supply can be used set to CV of slightly higher than expected max LED Vf and CC limit set to the desired LED current.
Most supplies allow Voltage setting with ease.
Those with adjustable current limits are not usually calibrated to allow the CC limit to be accurately set before use. An easy adjustment method is to short-circuit the output and adjust the variable current limit until the desired CC is achieved. In some cases the supplied CC at operating voltage may be somewhat different than CC at short circuit. (You didn't buy an Agilent sup[ply, did you?). To achieve a Vout closer to the desired one when setting CC a resistor load may be used such that R < Voperating/CC_desired and CC can then be adjusted,.