The FF7 Cloud Buster Sword is popular because it is a unique and iconic sword from a popular video game series. It is also a very large and impressive sword, which makes it popular for cosplay and display.
Additionally, the FF7 Cloud Buster Sword is associated with the character of Cloud Strife, who is a popular and well-developed protagonist. Cloud is a strong and skilled swordsman, and his Buster Sword is a symbol of his power and determination.