Whats the use of the different types cards in the card reader, can you link a site which describes the different cards slots and their uses found in the card reader.
As far i know the PS3 doesnt makes anything special with them, are just storage for general use, in OFW i guess most people was using them to store music, photos, video, etc... (the kind of content you can access from the XMB main icons)
In CFW, since some ManaGunZ versions ago, can be used to store and load game backups... are treated as another USB device
Btw, keep in mind are connected to a USB HUB... so pretty much have the same speed than the other PS3 USB connectors... or even less because the connections are like this (lets use the SD slot for the example):
Southbridge --- USB HUB --- SDtoUSB controller --- SD slot --- SD card
And in the other PS3 models, by using one of those "SDtoUSB" adaptors i mentioned like this:
Southbridge --- USB connector --- SDtoUSB controller --- SD card
As you can see we are removing a component (the USB HUB) because the newer PS3 models doesnt have a USB HUB... the 2 USB connectors are directly connected with the Southbridge
I never saw a speed comparison in between this 2 ways, anyway, they are never going to exceed the basic USB speeds because in both cases there is a "SDtoUSB controller" that needs to do the protocol conversions