>>53638012Like the other anon said, it just earns a buddy heart. Otherwise, it's just flavor-text.
The souvenirs you receive depend on the real world biomes recorded in the OpenStreetMap data they use, this is Niantic's idea of integrating the game with the real world.
Gifting is also a feature that's borrowed from the main series games, much like how XXL and XXS Pokémon were recently introduced after it became a feature with Legends Arceus, and Scarlet and Violet.
