A few questions about getting a (R4i) flashcart

I'm currently conflicted between whether to get a flashcart or a Cartridge to USB adapter, so that I can edit my Pokemon save files.

For reference, I have a DSi with the latest FW version(1.4.5)

If I get a flashcart will I be able to:

Use AltWFC with my cartridge(not with a ROM)?

Backup my cartridge saves/ROMs?

Edit my cartridge saves?




I really just want to be able to trade with myself and/or Pokegen Pokemon into my game.