No for the first part.Question: After spoofing, can you access eshop or game updates without nnu patcher?
Still currently confused why people would spoof and how its ever useful. Everything seems to work fine for me without it
For the second part, from what I gather, it stops giving you update nags and auto updates, even without dns setup. DNS setup is just so that you don't update by accident, or auto update if a newer system update gets released