Only if you want to takes pictures at the "extremes." Point and shoot cameras do a remarkably good job shooting typical daytime, outdoor scenes of people and landscapes. If that's your primary interest, the cost, weight, and complexity of a DSLR don't make sense, stick with a point and shoot.

This changes if you want to take pictures of stuff such as bugs, birds, night time sports, indoor theater/band/recital productions, house interiors, high speed activities, or slow changes. Bugs require a macro lens that allows you to focus close enough and get the magnification needed. Birds require a long telephoto lens so they can be photographed from far away and show up as more than a speck. Night time sports and indoor productions require a lens that is optimized for lower light (called a fast lens). House interiors require a wide angle lens, so you can be inside the room and capture a large portion of it in a single shot.High speed activities may require a fast lens along with a camera body that supports fast shutter speeds and can take photos in rapid sequence. Slow changes require a camera body that supports automatic picture taking every few minutes, hours, etc.