The difference is that say, I can give you a gold coin without paying a transaction fee, but the same cannot be done for bitcoin. This means that when all 21M of Bitcoin are mined the people transacting in bitcoin will experience an erosion in value when they transact, which may discourage transactions.
Gold derives its intrinsic value from the limited supply and easy transaction; I’m not sure if bitcoin can be the same.
Source :
https://www.investopedia.com/news/what-happens-bitcoin-after-all-21-million-are-mined/