Why do we need to shoot with a DSLR (at the very least)?

Image quality produced by a DSLR is higher than most fixed-lens digital camera although it is strongly affected by the choice of lens. A combination of low image noise and high retention of details, particularly at higher ISO settings, places DSLR ahead of fixed-lens. DSLRs can also capture more dynamic range than the vast majority of fixed-lens cameras. However, both types of cameras are equally capable in terms of color, white-balance and exposure.

The most significant performance advantage of a DSLR is in terms of speed. Compared to fixed-lens cameras, a DSLR focuses faster and shoots faster for longer. Most other DSLR timings are noticeably faster too, including startup time and shot-to-shot delay.

Focusing speed is important when capturing a moving subject. The faster a camera can focus, the faster it will take a picture. Shot-to-shot times and burst speed are also faster at maximum resolution on every DSLR than any camera which is not the Casio Exilim EX-F1. Burst-mode is mostly used in action and fashion photography where capturing a precise moment is paramount. Not only do DSLRs shoot faster but they can take more shots in a single burst at a constant speed. This increases the chances of capturing a decisive moment.

Source: Neocamera