The only limitation of this card is its incredibly difficult summoning mechanic, making it impossible for anyone else to summon
If, for some reason, you're looking at a Pokmon card to buy, but you can't physically hold and inspect the card for yourself (for example, if there's a global pandemic, the shops are shut, and you can't go within two metres of another person), always ask the seller to take an original, high quality photo of both sides of the card for you
I would add more copies to this deck, but maybe not more than three to make sure I don't die to the constant life loss
Lots of them
If your opponent has a Digimon with 10000 DP or less, you must choose that card and delete it
Its partially because there are better things to be doing in mono-blue (if you want to focus on fast consistent wins, that is), but I do think Cosima can offer a lot, particularly if built around