Lots of different metals could have been used instead of gold as money (platinium, palladium etc) but gold won everywhere on earth for some reasons, timing reason mostly (to costly to extract back in the day etc...)

Monero may have the required quality to be a good money but it's not perfect either, and it already lost the race against #Bitcoin IMO (again a timing and network effect issue)

Their is more txs in 7 bitcoin blocks that in a whole day on the monero network.