Pewter Crunchies are the only local specialty item introduced in a different generation than the region they originate from.
One of the described side effects of Pewter Crunchies is thirst, as described by Brock and an NPC in the gate between Route 7 and Saffron City.
In Pokémon Scarlet and Violet, a book found at Naranja AcademyS/Uva AcademyV reveals that Pewter Crunchies have failed to attain big popularity due to their "forbiddingly tough appearance" and "surprisingly thin flavor."