All the activities you listed are endgame. But as an example: You want to do reckoning t3. You have a light level of 673 and you can clear t2 without issue. You get an item level to drop later that day at 678. Do you infuse? Or keep it and wait? Infusing it makes almost no difference in your ability to clear t2, and makes no difference to t3 as you’ll have to infuse the same piece AGAIN later to be effective there. This is smart infusing.