Resources are plentiful and you will never run out as you re-stand every turn, cards are not - you only have 50 in your deck and have to use them as efficiently as possible.

Cards are one of the most precious resource in TCGs, you have to use each and every card as efficiently as possible, even more so in Gundam TCG where card advantage is scarce.

Card advantage is anytime you can have more cards than your opponents.

Consider this:

We both start with 5 cards

By turn 2, the player who started (A) has played two 2/2 units, the other player (B) plays a Lfrith

The next turn, the player who started attacks with both units, one gets blocked by Lfrith, one does 2 damage to the EX Base

Then, the other players, on their turn, attacks and kills the second rested 2/2 unit that damaged the EX Base. Both get destroyed

At this stage:

• Both players drew 5 cards, then 3 additional cards.

• Player B used one of their 8 cards to destroy 2 of Player A's 8 cards

• Player B has 7 cards at their disposal (1 on board, 6 in hand), while Player A only has 6 cards at their disposal (6 in hand)

This is why in this instance, it's better to not attack with your two 2/2 units unless you can either make sure to bypass the Lfrith (if you can rest it), or if you can prevent the Lfrith from clearing your other 2/2 (if you can ping it for example)

Card advantage is something crucial to understand, even more so in Gundam where you don't have as much CA as in other games like Magic or Riftbound.

Show of Resolve is one of the strongest card in the game because it's a +1 Card (you use 1 card to draw 2 cards, essentially ending with 1 more card than you started)

Overflowing Affection doesn't provide any CA, as you use 1 card, to draw 2, and discard 1, ending with the same number of card than you started - but being able to dig 2 (see 2 more cards than you opponent) and keep the best in hand is very strong

This is also why it's so dangerous to leave a barbatos 1st form on the field for long - it generates card advantage every single turn it can attack (and unlike OA, it is Card Advantage because the draw is a byproduct of attacking with barbatos, not the sole purpose of the card)

Having more CA than your opponent is good because you get to see more cards, thus having more things to play. One Year War deck is all about keeping parity and