1. To have an external battery charger to charge the battery of the RX-100, while I take pictures with the camera or the camera does not need to use as a charge-slaves.
2. The USB cable also included: yes, it is already in this camera, but I like to have a second one for my travel kit. It is, as I have read, not really proprietary, but it's just not a Mini-USB (eg as with Nikon DSLRs) or Micro-USB (eg as with Nikon Coolpix or Lumix). (My Garmin Nuvi Car GPS device uses the same cable to connect it to the PC.)
3. The battery! OK, the replacement battery I can buy individually, but who looks together count the prices of items that almost nothing of the battery cost in this kit. As written just in another review, I did many years ago lost the desire to experiment with replicas, I will have to take into account any failure rate, and I want to (at worst) and at 1 year non-use (I know you want to do not) have the certainty that the battery load can still be.
The charger is not the most graceful, but it has power and charges the battery much faster than the in-camera variant example of RX-100. It has a charge status indicator (only a few LEDs), here comes the only not so great point: the functionality you have to remember that the battery will not be (entirely) is fully charged when all 3 LEDs are lit (it is according to instructions only 95%), but if after the LEDs. So you can live, normally you will not stand by and "funny LEDs look", but anyway the battery using the (pre / post-lunch) leave the unit and then see at some point that the LEDs have gone out.
Another plus (and here the in point 2 mentioned USB cable says): It can also operate as a USB charger and recharge any suitable device with a USB charging cable for the charger has a USB port (thus execution as on the PC). And with the included USB cable you can then connect the RX-100 choice (with battery in the camera) and upload in this way. But be careful: you can only select one variant at the same time - the charger has a switch that selects the modes USB charging or batteries installed.
Oh yes, the charger has a built-in type slide plate that makes it for other (Sony) battery types compatible; copied from the Sony website:
*** Attention, not tested by me! ***
"The charger is compatible with 7 types of batteries, including NP-BX1, NP-BN1, NP-BN, NP-FG1 / BG1, NP-FD1 / BD1 / FT1, NP-FR1 and NP-BK1"
*** Attention, not tested by me! ***
(Since this kit contains the NP-BX1 Sony RX-100 it is anyway only the interest that another Sony equipment with the mentioned battery types have)
In a nutshell: for me, a great add-on product to the RX-100, with practical accessories.
