Following oric_dan's excellent commentary is one thought ..
Re: tri-state output's., A 4K7 resistor used as a static pull-down for the led driver port (whether Fet or BJT) will keep the driver output's at a low condition during the reset or power down (sleep modes) thus preventing
"Un-Defined" behavior when the port pin tri-states during power down or the aforementioned sleep mode(s).
Perhaps a few parts more but the parts are used to eliminate "Undefined" states.. Thus making writing code that much simpler... and a 4K7 ohm resistor requires 1 mA... When the port is high. 10K is 500uA and 22K is ~ 250 uA.
Simple basic Electric Engineering 101.
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