Like I've said quite a few times, I reserve using my own decks for PvP, and use prebuilt, unoriginal decks for level 3. Of course, I usually alter the prebuilt deck to fit my playstyle more (remove this card for that card, etc.), and I'm perfectly fine in using it to grind electrum. On the other hand, I also love making new, semi-fun decks, especially ones that use new cards, to be used in PvP.