Im looking at you Krenko's Buzzcrusher)
The short answer is that if you are paying more to kill a single threat card than that threat card actually cost to play you will often end up falling behind
While its less true than it used to be (thanks to FIRE design, cards designed for Best of 1, and increased modality/card draw in general), its still a key part of gameplay and it feels like what this mechanic, and in particular, gifting a card, was designed around
Each day leading up to the holidays reveals a surprise item, including: 8 foil Pokmon cards with a snowflake stamp 6 booster packs 7 mini 3-card fun packs 2 coins 2 sticker sheets 1 Pokmon TCG Live code card Additional holiday-themed accessories and goodies Its designed to be both a fun countdown and a value-packed gift
Trainer - There are multiple different types of trainer cards (items, stadiums, and supporters) that a competitor can use during a battle