Digital piano is a setup that includes a keyboard controller and a sample playback device that specializes in different piano sounds. Digital piano are available in multiple sizes and shapes. Some are lookalike upright acoustic piano. Some resemble the look of a music workstation or the modern synthesizer. These are lighter in weight as there are no internal speaker systems fitted. There is no internal amplification setup too. Years ago the acoustic piano was more in use, and the digitals were considered to be crappy sounding. At that time, digitalization was not much successful. But today it is the digital era.
Everything thing used is digital so why not a digital piano. With time, your acoustic piano must have started showing some signs of wear. It is better that now you go for the digital ones. Acoustic piano starts detuning when it gets old. Digital piano is similar to the acoustic piano in many ways be it in feel or sound. They have multi sampled piano sounds which tips that the samples are recorded from a real piano.
Different level of loudness is available for different tunes. It implies that when you press a key on the digital piano the recorded sound is played. The loud sample is utilized when you particularly pound on a key. This is same like the real piano, when you applied pressure to a key a louder note came out. In fact, some of the latest models of digital piano have a different set of samples for each key. Some experts may call out some flaws in the digital piano and may not consider it worth an acoustic one, but for an untrained ear there is no noticeable difference. Both acoustic and digital are advantageous in their own way. Just the fact is that the digital ones are more handy and more techno.