But is it differs from fiat digital currencies in several important ways?
You know its good that you are trying to know more about bitcoin and cryptocurrencies but I doubt it is being useful for you, because you create a new thread everyday and then ghost it like you never made it. Its worth posting if you actually read the replies and try to communicate with others. This is a forum you know, just my 2satoshis. 
Yes it is a lot different from traditional currencies, which you can find out by google as well much faster than asking here. Of them what I mostly value it for are that it is decentralized and the deflationary nature of the currency. What I also dont like is the pseudo-anonymity would have been great it if was completely anonymous or the opposite, not something in between.