With richer colors and supreme contrast, OLED displays on smartphones not only make operating systems, apps, and content look better than traditional LCD displays, they're also more power efficient, too. One of the ways OLED displays are more efficient is that pixels can essentially turn themselves off when displaying the color black, and they don't shine as much as LCD displays when displaying certain colors and certain brightnesses. That power efficiency can often lead to better battery life.
With that in mind, OLED displays seem like a no-brainer for laptops, but most laptop makers still use LCD displays. There are some laptops that come with OLED displays, but not many.
One reason why more laptops don't come with OLED displays is cost, as devices with OLED displays tend to be more expensive. Still, cost can be mitigated by manufacturing advances and production volume, and it doesn't look like much has been done to mitigate the cost of OLED for laptops — yet.