I had used my sp4 for more than a year without any protector, writing on it. No issue. No need to worry so much. It is built to use with their pen, unless u use normal pen to write on it.
Afraid finger nail or surface pen might scratch it... lol
Still sourcing online for a screen protector and skin
Will update u guys once done
So far i m happy with my SP 2017. Only complaint is that occasionally it will hang for a few seconds while surfing or watching vid