Bigger, better monitors are important accessories for the productive developer. Integrated graphics can't power those monitors. Most laptops sport only integrated graphics. Therefore most laptops are insufficient for the productive developer nowadays. There are a few scenarios where the developer's hardware should certainly be better than the user's, and screen space is one of them. Old hardware is not an excuse to stick to 1080p. Every developer should have moved to the much more spacious 1440p or 4K by now.
As a reasonably productive developer who has used both 4K and 1080p displays regularly, 4K has done very little for my productivity. It just looks good.
