As many Dragon Ball fans know, through the course of the story, his "move-set" changes quite a lot. This particular version of Goku is from Dragon Ball Z: The Tree of Might.
Based on that movie, this version of the Fighter has the potential to one-shot an Enemy with a powerful spirit bomb, dealing huge amounts of Damage. SP Goku PUR also has a Special Move Damage Boost, making him even more deadly.
Lend Me Your Energy!
This Fighter's strength lies in Complex Damage and avenging fallen Teammates. The One-Handed Spirit Bomb Special Move gets three different Ability and Move-based Buffs.
The first one is "Lend Me Your Energy", an Extra Move that increases the power of his Special by 30%, 70%, and 120% respectively for each time it's used.
By the third use, the Special Move is also granted a 70% chance to inflict Faint--a deadly status that makes the opponent completely unable to move for about 3-4 timer counts--assuming the Enemy managed to survive a 120% Damage Boosted Spirit Bomb in the first place.
The second mechanic supporting the One-Handed Spirit Bomb is his Main Ability, which Draws that Special Move. and Restores his Health by 20%. This coupled with his extremely high Defensive stats makes him even harder to take out. Saiyans don't have many Tanks, so this is a huge help.
The third and last mechanic supporting his Spirit Bomb is his secondary Crisis Unique Ability. When both of his Teammates have been killed and SP Goku PUR is the last man standing, he gets a 50% Special Move Damage increase.
In order to maximize this Fighter's Damage output, he needs to draw those Extra Art cards. He holds two generic Strike and Blast Arts Cards, which aren't as useful for what he's supposed to do.
To avoid relying too heavily on the chance, this Fighter needs other Teammates with held Extra Cards, such as SP King Dabura BLU.
While his balance update Buffs do a lot to keep this Fighter relevant, he's still overly reliant on Complex Damage through his Special Move. Not only are Special Moves rare to draw after the initial Main Ability pull, but Complex Damage is calculated based on averaging Blast and Strike Attack.
In Saiyan teams, he can be a decent choice. He's one of the few SP Rarity Purple Saiyans, making him a valuable pick for color variance.
The only problem is that his Z-Ability is color-locked. This means he can only be run as a core Fighter or as a bench to Buff a potential Purple core.
Purple Color Counter
SP Goku PUR has a great double Buffing Z-Ability for Purple Fighters, so running him at the very least as a Bench Buffer is pretty much mandatory.
Difficult and ineffective Crisis Unique Abilities.
SP Goku PUR is too focused on special move buffs and last man standing. His stat re-balancing helped bring him back to PVP viability. He became more consistent, but he doesn’t make for the best Crisis Fighter.