Right now, as far as I know, cards in Ante are removed from decks for the duration of the match. This causes issues with deckbuilding both for the player and the enemy. The issues can be specific like making it impossible to use Biovisionary reliably unless you have 5 in the deck, randomly reducing effectiveness of cards like Pack Hunt, or cards that take into account how many copies you are playing, or it can be general because it can mess up the counts of any particular key card in any deck in any match.

I could explain at length how this is an enormous problem. A deck with 2 copies of an important card can be playing a match with only one copy present, cards which the enemy deck needs to reliably draw (and are as such 4-of) can suddenly be 3 of, etc. If you're just starting out and ante takes out a key card the relative power of your deck can easily take wild swings. It's also rather tricky to design & test AI decks properly when any card can just disappear every time. Some cards you just can't give too many copies of to the AI, because it would have overly explosive games when it stacks them, but ante messes up any lower counts of cards. Depending on the number of copies it makes any card either 25%, 33%, 50% or 100% less likely to appear

It would be extremely beneficial if ante was reworked to just mark the cards in question without removing them from decks, and any card that "antes" additional stuff in-game to just exile and mark it as ante instead.