I kept mine in a box because I had a Vaporeon in my team and no Pokémon can replace a Vaporeon. 😉
On the note of guaranteed shinies: yes, I liked that too, and I liked how in Pokémon Legends: Arceus - which I am currently playing - there is a guaranteed shiny Ponyta. It felt like a nice callback to the red Gyarados, and a good chance to get a shiny for those who haven't played the old games.
And, staying true to the tradition, I never added the Ponyta to my team either. 😛 I mean, why would I, when I have an awesome Typhlosion?