They had to make sense in a duel
Although similarly-named Pokmon-EX were present during the XY era of the TCG, they were always Basic Pokmon (or Mega Evolution), even for evolved Pokmon such as Charizard, meaning actual evolution cards (Stage 1 and Stage 2) became less and less used and the gameplay was focused more on hard-hitting Basic Pokmon
It juggles counters and impulse draws, has solid, aggressive keywords, and you can always run out the front half and transform this later if youre in need of extra cards
Prank-Kids Battle Butler can wipe out your opponents monsters when it is Fusion Summoned by Tributing itself
Here's how the myth-vs-fact breakdown plays out for anyone still deciding
To verify your cards edition, inspect the font, year(s) listed on the card, or consult the Ultimate Pokemon Guide