Series Resistor in MicroSD Card VCC on Dfplayer

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Hi.

I am decanting some of the Dfplayer design (YX5200 based) onto a PCB.   The memory card interface has a 4R7 resistor in-line with the VCC power supply and a decoupling capacitor.  I am confused as why this is there as it seems to be going against normal design principles of minimising the supply impedance to reduce voltage drop and current spikes. See attached circuit diagram.   Any insights?

thanks

[SeanB]

Capacitor provides the low impedance supply, and the resistor is there to prevent high frequency noise from the main supply reaching the card, plus also providing a current limited supply to the card in case the card shorts out, so the board does not get damaged. Resistor is a lot cheaper than a polyfuse, which would do both functions, and provide better current limiting, but costs 100 times more than the resistor.