"idk man just make a card that can get a super easy 18x"
324x for something so fucking simple is just idiotic
The multiplier probably doesn't need to be that high, but it's by no means easy. Try matching 3 5-lines of three different elements every turn. You can't do it consistently at all.
Fullboards like Leilan are still programmed to only work with the base case of 3-match, so if any of the three colors spawn with less than 5, and due to Murphy's Law they will most of the time, you are instantly hosed.
EDIT: Also you aren't able to heal unless you match 5+.
EDIT EDIT: I have just realized that there exists an instant lose condition for these kinds of leads:

no orbchange actives up, enemy doesn't change orbs when it attacks
gg