Are studio monitors good for casual listening?

Genuinely, yes — with eyes open. Powered monitors bundle amp and speaker, image beautifully at desk distances, and their neutral voicing is a feature once you acclimate. What you give up versus hi-fi speakers: a warmer “voiced” presentation some prefer, and living-room-scale output — nearfields are designed for 1–1.5m. For a desk or small room they are often the best value in the building.