Scanners are definitely better than a phone camera, but speaking from experience, having decent photography skills with a phone can help too. It's not a replacement for a scanner, but I actually photograph my traditional art with my phone's camera and it works the same as a scanner if you get creative with it.

I think I have been getting better at angling the phone so it doesn't leave a shadow on the page, so you have a point, that's a skill too!