I'm pointing out that the statement in regards to the current system is overly simplified. Take a while to read the entire post and understand the context before you ask irrelevant questions.
You're focusing on what you had to think about in the old system and ignoring what you have to think about in the new system. No wonder you think it requires less thought.
In the old system, you played the card ASAP because otherwise you'd have delayed your next cards. So you used a simple set of rules based on which job made the most use of the card. You had different ways to transform the cards - which you absolutely needed, because the system revolved around getting rid of the useless cards as soon as possible to make room for the next spread Balance.
You needed to know what card was most beneficial to what job. Now, you need to know when the card is most beneficial to each job.
Conveniently, you can now hold onto the card without losing draws, allowing you to choose a better time window to use it.
The card lasting for 15 seconds means that it's important for you to use it when your target has a burst window, rather than immediately or whenever you feel like it.
No job does constant DPS throughout the entire fight. That BLM pulling 16k dps might look like a juicy target. But if you throw your card whenever you feel like it, you risk giving them a buff during the 12k dps umbral ice phase, rather than the 20k dps astral fire phase.
Here's another scenario: You have a BLM and a MCH in your party. Do you automatically use the card on the BLM? If you do, you're not getting the most out of your cards. MCH has burst windows that can go up to 25k, which BLM cannot hope reach without extreme RNG.
The new system is only less thoughtful or involving because you choose to ignore the more nuanced aspects.