Some of the advantages of dSLRs are more closely related to the digital single lens reflex design.

• Better lenses. You might argue that a non-dSLR eliminates the need for interchangeable lenses. If your 12X zoom EVF camera offers all the focal length equivalents between 28mm and 336mm, who in their right mind (other than architectural photographers at the wide end, and pro sports photographers at the tele end) would need more? However, I maintain that even if you super glue your lens to a dSLR (transforming it into a noninterchangeable lens camera), the dSLR’s zoom lens will provide better, sharper pictures than what you can expect from a non-dSLR’s optics.There’s plenty of room for argument here, but, in general, it’s easier to design a high quality lens for an SLR’s larger sensor than it is for a tiny point-and-shoot’s CCD.
• Easier upgrading. Conversely, you don’t have to load down your camera with features you don’t need. As I write this, only a few non-dSLRs offer image stabilization (which minimizes blur caused by camera movement at low shutter speeds). If you want that feature in a non-dSLR, you have to specifically purchase a camera that offers it. (At the time I’m writing this, the Konica Minolta 7D is the only dSLR with anti-shake technology built into the camera body itself.) A more powerful external flash is an easy addition, too, compared with point-and-shoot digital cameras, many of which allow no external flash at all (other than slaved units).
• Better use of power. You’ll find that your dSLR camera’s battery will last much longer than you expect. Most digital SLRs switch off their autofocus and autoexposure systems automatically if you haven’t used them for a few seconds, and the power-hungry LCD is on only during picture review or menu navigation. You can leave a dSLR switched on for days on end without depleting your batteries. A non-dSLR with an optical viewfinder is guaranteed to chop off heads, or worse, as you compose your pictures.
• True “what you see is what you get” composition. A non-dSLR with an optical viewfinder is guaranteed to chop off heads, or worse, as you compose your pictures. The LCD on the back of the camera provides a reasonable facsimile of what the sensor sees, except you can’t see it in bright light, and the details on an LCD that can be as small as 1.5 inches are too small anyway.