No need to be snarky or anything like that. What makes it more popular than Delphox or Chesnaught? A lot of people the other two just as much, yet we only see Greninja. To a lot of people, Greninja was designed to be 'popular' but that's not how popularity work. Sure a ninja frog is cool and we have Naruto to thank for that - heck my naruto deck was ninja frogs but there was like no time to even get to like the pokemon. They just showed it and said, "yep, popular". The honest question here is do you think it would be as popular if it wasn't so in your face versus the other two?