Great plate day 1 (20 roll) yield:
3 seal frag
1 purification rune
1 purification protection rune
5 bbq (x2)
6 coin (x50k)
2 adv refine rune
2 lv 3 magatama pack
Total: 227.5 coupon, 300k coin and 10 bbq
Not as bad as I expected it to be, having a positive return compared to what key would have cost. Maybe I'm just lucky today, who knows. Still not worth spending on, compared to lucky board, but at least thus far not nearly as bad as some people make it out to be.
We'll see how it goes for day 2.
PS: I'm measuring lv 3 magatama pack to be 41 coupon, which is roughly the average of the lv 3 magatamas(converted from lv2 or 4)