Bitcoin is first of all digital currency and on top of that decentralized. Many however consider and say that bitcoin is digital gold. If we compare gold and bitcoin in some way there are some differences but also they are unique, every in his own way. Only downfall can be trading them, both have solid gains but many are now in bitcoin more cuz of the high price.
When peoples talk about gold they talk about something of great value by excellence,the same for diamonds or things like that, and I have to say that there are not some differences only but they are completely different inwardly while one is tangible, physical and can be touched the other does not, can not be touched and is not tangible or something physical,the only thing that both can have in common is that people consider them as something of great value and that's why they compare them, but nothing more.