I think so, especially if you want to do other playthroughs, but don't want to lose your Pokemon.  It is free to store 30 Pokemon, but no transfer from Bank.  Or you can do different payment plans, best being $16 a year, to store 6000 Pokemon, transfer from Pokemon Bank.  You can get a Japanese Pikachu from Switch version, a Kanto starter from Mobile version, and if you complete a challenge on Mobile, you get a mystery gift in the app for a Pichu.  Also, Mobile version allows you to trade via GTS.