Splitting power to two devices (Raspberry Pi & LED Matrix)
Your supply is correct for this situation, but don't generalize this.
Your schematic shows the devices as resistive loads; the implication there is that the current drawn is proportional to the voltage input.  That is not the case for either of these devices, and this would not work if it were.
Your devices each have their own power regulation, so that they draw what power they need from a constant input voltage.  Here all you need to consider is the desired input voltage (range) and the maximum current that each may need; your supply matches the voltage requirement and will handle the combined (summed) current requirements of both.  So this is good.