Theres a big difference between a four- and a three-mana spell, and Gideon of the Trials will slot into hyperaggressive decks even with Gideon, Ally of Zendikar in the format still
With a lot riding on Historic, it makes sense for Wizards of the Coast to be highly-attuned to player desires, especially pre-launch - a healthy Historic format could create long-term investment in the MTG Arena platform that wouldn't have been possible with just rotating Standard formats, and it could spill over into paper Magic: The Gathering should it prove popular enough, too
What is the rarity of this Beheeyem card
Games like Pokemon TCG Pocket that arent under the spotlight
Perhaps if Charizard G had some powerful attacks to help avenge its Level Up, but alas, it does not
Its certainly a worthy addition to your collection whether you love collecting Charizard cards or just love this particular card itself