I have exactly the same setup - an iOS (iPhone5 right now) wall-to-USB adapter and a 3DS to USB cable - and it works fine for me. The 3DS detects that it's plugged into power and does charge.
I use this set-up occasionally when I'm traveling and don't want to take apart the whole cradle and charger system. It hasn't caused any harm yet, but I don't expect Nintendo to ever officially endorse it.
Cons of Downloaded Games:
- Can't share with friends
- Difficult to move from system to system
- Leaves cartridge slot empty (no placeholder)
Cons of Physical Cartridges:
- You are unable to back-up data into an SD card
- Need to carry/swap cartridges
- No possibility of recovery*
* Never assume Nintendo will get your digitally downloaded games back either. That being said, anecdotal evidence:
I recently purchased a 3DS and purchased and downloaded a game. A week in, my hinges began loosening, so rather than sending it in for repair, I wanted to replace it at the retailer. I called Nintendo support, who told me that if I made sure to register my current 3DS first, and write down my serial number, they would be able to initiate a system transfer remotely, after I had exchanged my system. They said this is a new option, and I think it seems to be a step in the right direction. I swapped my system, and called them back. Unfortunately, their phones have been too busy to even put me in a queue for the last several evenings, so I can't yet confirm that this will in fact work, and am now left with a 3DS and none of my downloaded games. For now, this is definitely another pro for cartridges.
Really, it comes down to security of a physical copy vs convenience of a digital one. Personally it's physical cartridges for me from here on out, until Nintendo moves to a real account-based system.
Best Answer
From the Terms and Conditions on www.paypal-gifts.com
To answer your question: No it is not possible to buy an UK Nintendo eShop card without a valid UK Paypal Account on paypal-gifts as long as the retailer dont say so.
Here's a list of retailers (in europe) ordered by country where you could buy eShop cards but i dont know if you'll find UK cards there. I'm sorry but I wont tell you were exactly you can buy what you're looking for because questions like "where can i buy XYZ" are not allowed neither recommendations are but Yes you can find what you're looking for if you take your time searching for it.