It provides natural card advantage, fills in for your missing rogue, then provides a massive pump to your creatures each turn once your partys full
(And, of course, the sweet spot is when you have very strong tribal rewards and very strong individual creatures!) Sometimes you might have to play a couple creatures that are just below the bar of normal playability, but you certainly don't want to fill your deck up with those
Or would you prefer to spend them on cards for your cards or duplicates for Flairs
Each era introduced distinctive mechanics: ex Pokmon, Lv.X, Prime, LEGEND, Mega, GX, V/VMAX, and now Mega Pokmon ex
Judges have a long and storied history of trying (sometimes in vain) to explain split cards to players