Paint primers are necessary, irrelevant of the paint brand, if you want to ensure adhesion, durability, color depth, and longevity of your painted surface.
Primers help paint adhere better to the surface and reduce the likelihood of peeling or flaking over time. They also seal porous surfaces, preventing the absorption of paint and resulting in a more even color and sheen. Additionally, primers can block stains and odors, especially on surfaces prone to discoloration or contamination.