The stats of the 39 Planetary Qualifier don’t lie: Boba Fett Set 1 represented
– 42% of TOP8 leader share
– 57% of Winner share
“This means that, starting on November 8, the Boba Fett leader from Spark of Rebellion will not be legal to play in any Premier format events; he will remain legal in Twin Suns, Draft, and Sealed.“
Source : https://starwarsunlimited.com/articles/a-leader-suspended
You can find season 0 Planetary Qualifier statistics here, thanks you @pasqwalle from discord for compiling all that data.