Can I use a regular desk lamp instead of a monitor light bar?

You can, but desk lamps take up valuable desk space and often create screen glare because they are not designed to direct light downward onto the desk while shielding the monitor. Monitor light bars mount directly on top of your display, use asymmetric optics to illuminate only the desk surface, and take up zero desk space. The focused, glare free lighting is the main advantage over a traditional lamp.