Okay.
1. You can attach any number of unique lenses to provide anywhere from a wider angle than any point and shoot to a much longer reaching telephoto lens than you can find on even a prosumer super-zoom.
2. Sharper lenses; there are no P&S cameras that have absolutely no issue with purple fringing or resolution loss (softness) at the corners.
3. Dynamic range is greater with almost all dSLRs than P&S cameras; they can capture considerably more contrast in a scene without making completely black and completely white areas. Newer dSLRs can adjust the curves even more to offer more retention of highlights.
4. ISO sensitivity for NOT using flash in dark places: almost any dSLR will beat almost any P&S in terms of image quality and lower noise.
5. Faster reaction times for many things; faster burst mode in many cases (3, 5, 6, 8, or even more frames per second); many of them offer the ability to not have to refocus with every shot, allowing faster shooting; many of them have an AI servo that constantly focuses on a moving target; some of them have PC sync ports and all of them have hot shoes; many dSLRs have better battery life than P&S cameras; many dSLRs have much better viewfinders than P&S cameras; many dSLRs can do longer and shorter exposures than P&S cameras.
6. dSLRs have better processing algorithms that allow for better overall image quality without oversharpening and artifacts reducing the quality of the image during processing.
7. There is no P&S that can offer apertures like f/1.4 or produce nearly the same soft bokeh as a dSLR under similar cirtucumstances (like focal length and subject distance).
8. There is greater ability to make use of on and off-camera flash units, like hot shoe flashes and studio strobes.
9. dSLRs look more impressive.
1. You can attach any number of unique lenses to provide anywhere from a wider angle than any point and shoot to a much longer reaching telephoto lens than you can find on even a prosumer super-zoom.
2. Sharper lenses; there are no P&S cameras that have absolutely no issue with purple fringing or resolution loss (softness) at the corners.
3. Dynamic range is greater with almost all dSLRs than P&S cameras; they can capture considerably more contrast in a scene without making completely black and completely white areas. Newer dSLRs can adjust the curves even more to offer more retention of highlights.
4. ISO sensitivity for NOT using flash in dark places: almost any dSLR will beat almost any P&S in terms of image quality and lower noise.
5. Faster reaction times for many things; faster burst mode in many cases (3, 5, 6, 8, or even more frames per second); many of them offer the ability to not have to refocus with every shot, allowing faster shooting; many of them have an AI servo that constantly focuses on a moving target; some of them have PC sync ports and all of them have hot shoes; many dSLRs have better battery life than P&S cameras; many dSLRs have much better viewfinders than P&S cameras; many dSLRs can do longer and shorter exposures than P&S cameras.
6. dSLRs have better processing algorithms that allow for better overall image quality without oversharpening and artifacts reducing the quality of the image during processing.
7. There is no P&S that can offer apertures like f/1.4 or produce nearly the same soft bokeh as a dSLR under similar cirtucumstances (like focal length and subject distance).
8. There is greater ability to make use of on and off-camera flash units, like hot shoe flashes and studio strobes.
9. dSLRs look more impressive.
