Just because UWP targets all Windows 10 platforms, it doesn't mean a developer will take all of them into account.
Currently most UWP developers only care about desktop as target platform, so if it happens to work and be a good UI/UX in a e.g. 7" display it will be by accident.
One needs to take responsive design and API contracts into account, to make a good UI/UX across all supported platforms.
Just because UWP targets all Windows 10 platforms, it doesn't mean a developer will take all of them into account.
Currently most UWP developers only care about desktop as target platform, so if it happens to work and be a good UI/UX in a e.g. 7" display it will be by accident.
One needs to take responsive design and API contracts into account, to make a good UI/UX across all supported platforms.