During the Nintendo Treehouse: Live presentation, Nintendo went over the restrictions people will encounter when using Pokemon Sword and Shield with Pokemon Home. It turns out, not all Pokemon stored and traded with the program can come over to the Nintendo Switch game. Only ones that appear in the Galar Dex, the regional Pokedex for the game, can make the leap. Pokemon Sword and Shield will be able to send any and all Pokemon you catch in it into Pokemon Home once it kicks off in 2020.
This decision was made for two reasons specified during the stream. One thought was to keep the roster balanced. The other had to do the ability to include updated and detailed versions of Pokemon in Pokemon Sword & Shield. The goal was to make sure all characters who will appear in the game look as expressive as possible.
Pokemon Sword and Shield will come to the Nintendo Switch on November 15, 2019. Pokemon Home will launch in 2020.