The main difference between an electronic piano and that of an acoustic piano is that the digital piano is an electronic instrument, much like the organ, that is able to simulate and replicate the sound of a piano, and in the sense of the word, the sound of an acoustic piano. With an acoustic piano, you get to hear its beautiful sounds each time you hit those ivory keys, as a result of a combination of many components working together to produce the sound, which includes piano strings, keys, hammers and the soundboard. With an electronic piano, you hear the sound of a piano as a result of it being reproduced from electronic chips, circuits and sound speakers built into the instrument.
The problems or disadvantages of an instrument like the electronic piano are that you will never be able to fully replicate the unique tone and harmonic mix of an acoustic piano. While electronically the mix of different notes can be digitally produced and enhanced, to a trained and cultured ear, it will never sound the same with warmth and breadth of an analog produced sound as that from an acoustic piano. So while many electronic pianos today sound almost as similar to that of its acoustic counterpart, you lack the warm tone of the latter, and even the touch and feel of an electronic piano can sometimes be too cold compared to that an acoustic piano.
Many electronic pianos have piano keys that are now specially weighted and graded to ensure as much resemblance to that of an acoustic piano as possible. However, most electronic pianos are not able to reproduce the kind of touch that many pianists demand from their instrument, such as when they apply greater force to that of an acoustic piano, the dramatics that action provides to the sound of each key would be relative according to the amount of force applied on the piano key, and this is the kind of relationship that exists for an acoustic piano that an electronic instrument will never be able to fully simulate to the complex and analog nature.
The advantage of an electronic piano, on the other hand, is that the maintenance and care required for it will never be as extensive or expensive compared to that of owning an acoustic piano. With the latter, you will definitely need regular and constant maintenance of the instrument and its different components, such as the piano keys and strings. For example, you have to avoid the gathering of dust and rust on these components, or they will drastically and negatively affect the sound quality. With an electronic piano, all you need to ensure is that the instrument is kept away from heat and humidity, and by nature of it being an electronic device, it can last much longer if such conditions are met. As a result, you can save considerably on your budget when using a digital piano and learning how to play the piano.
Another pro to using an electronic piano is that you can actually play different instruments on it, or rather, you can simulate playing other instruments. Due to its electronic nature, a digital piano can come with sound samples of other instruments such as the flute, violin or even guitar. You can even add on extra instruments as and when you find them or like any. Once done, you can play the violin on an electronic piano, but just like playing an piano. This is incredibly useful and provides maximum cost savings for the recording musician who is unable to afford or even find another musician to play and record different instruments. Using an electronic piano, all the recording musician needs to do is to compose and play the various instrument parts, on his piano.
With the above, you would have learnt the key basic differences between an electronic piano and that of an acoustic piano. The critical pros and cons of both instruments have also been presented, and they should all help to provide you with the necessary information and details to make a well-informed decision on which of the two forms of the piano instrument to purchase and learn on.