As you see in clearly written detail, you lose data associated with the account and purchases made that are linked to it.
But, you can reactivate the account within 30 days of deleting it by simply logging back in.
So, please, no complaining about how “NINTENDO SCREWED ME OVER AND I LOST EVERYTHING” after you delete your account and let it be removed completely.
When it’s written right there in front of you.
If you delete your account with a lot of stuff on it, and let it be fully deleted it’s your own fault.