Lasers, just like in scifi, are the inevitable future of warfare, especially with regards to air and naval combat. While laser guns in the style of Hollywood might be far off (and impractical, at least related to bullets and guns), ships and planes with powerful power sources could easily field them.
Lasers have not historically been on the battlefield as weapons, therefore history cannot be used to indicate whether or not they should be banned from use on the battlefield as weapons. Lasers have conventionally been utilized by targeting systems, making them more precise and minimizing collateral damage. Because lasers have not been utilized as weapons, there is no historical context to ban them.