Card games take "options" and fundamentally change their surface area.
Imagine you're playing a strategy game. You have literally 100 different diplomatic options for interacting with another country. This is pretty awesome, but it has a lot of implications:
-At any given time you can think about "Oh, should I do this one too?" for a boatload of these. This can make the game take way longer, because there's way more options to consider.
-Depending on the degree to which diplomatic options are constrained by resources/cooldowns/limiting conditions, you may have turns where you're doing a ton of diplomatic options all at once.
Cards break actions like these down into essential units, changing the "surface area" of decision making and changing how you acquire options. Instead of diplomatic options being limited by some sort of resource or conditions or cooldowns or something, cards instead funnel that an emphasized focus on a fundamental distinct action, in a format that is both generalist and also highlights the specific actions you've drawn.
In contrast, options having a sort of omnipresence and not being "mobile" or "interchangable" has some nuanced effects. Also, having such a long list generally results in developers cutting the list down because of the downsides, so turning options into cards can result in more options in practice- more distinct actions can exist without troublesome UI or "choice surface area" downsides or certain types of balance concerns.
Additionally, breaking things into cards is an abstraction that makes it easier to digestibly add permutations- like "oh, this is this variant of this card" or "oh, this card is buffed now."
i want to articulate this more but its difficult and i have so many drafts lmao
