Not really, especially because when playing on the move I'm always wearing headphones/earbuds so the device's internal speakers are irrelevant. The screen size

Not really, especially because when playing on the move I'm always wearing headphones/earbuds so the device's internal speakers are irrelevant. The screen size issue is marginal at best. You're trading it for a bulkier device: you might prefer that, and that's cool, but it's not an obvious and objective advantage for everyone as a result. (Assuming all things equal and you've chosen the separate controller route: if not you lose the bottom screen anyway, because it's used as the controller.)