This system makes collecting less enjoyable than rewarding for those who've spent time and money on finishing previous expansions
I admit it: I adored the first Mystery Booster experience at conventions
You'll eventually reach a point where you got most-to-all you wanted with your jobs and skills, a point where it's better to replace JP Up with a support skill that directly helps you in battle, but from the early to mid game there's no reason to not have all your human units running this as their support skill unless you're explicitly handicapping yourself
Endless Atlas gives you constant card draw so long as you have three lands with the same name, War Room lets you pay one life to draw a card, and Minas Tirith draws a card so long as you attacked with at least two creatures
I don't deliver, so please don't ask, however, I am willing to ship with payment through Venmo or Paypal
It will vary by set size and how many Mythics the bots deem "crap" and pass all the time, but half is a decent approximation