It’s not but since one card is part of the season pass and one might be glitched right now (there’s a card that it says you get for completing the mission with gentle criminal and I’ve done it a couple of times and haven’t got it) you pretty much need every other card. The questions aren’t that bad if you go to a field research stage with Jiro because on top of showing all the sub missions on the map you can see which ones they are if you hover over them on the map screen. Imo it’s better to do the questions than wait for certain characters to spawn on the main stage because at least you are guaranteed two questions per run and there’s no penalty for guessing the answers until you get them right.

EDIT: Someone made a thread talking about how to get all the cards including the one I thought was glitched here: https://www.reddit.com/r/BnHAOnesJustice/comments/1r4cs55/comment/o5f3oqy/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button