But aren't these for making a bar display? That is a display where the number of bars or LEDs lit is proportional to the applied input voltage.
ie. All the LEDs light up if the input voltage is high enough (eg. +5V).
They work great as a switch for multiple LEDs. You get constant current drive with zero external components, they're quite cheap, don't take up much space on a PCB and PWM works perfectly.http://www.shenzhensum.com/products/datasheet/KA2284%20.pdf
The only real downside is you can't set the LED current, it's fixed at 15mA.
I don't see how that answers the OP's question.
One Arduino output can control an awful lot of LEDs using those.