Hello.
For the USB Cable - connect and have access,no pulling in/out of the Memory Card.Needs an USB Port on your PC.
It spares the Card Slot AND also an Adapter (if you use microSD Adapters).
For the Card Reader - if you purchase an USB 3.0 Modell and your PC supports it too,you have maybe faster Transfers (for Example your Games).
For the microSD Adapter - there is maybe a
"small" Change your microSD Cards are not recognized correct with this Adapter or wroking correct inside your PSP.
If all works you have lots of Space for little Money (Bigger Sony Memory Sticks are unfortunately very expensive..).
Thank you.