Monero and other currencies have value because people are wiling to trade other things for them.
If none will trade anything for a currency, then it has no value.
Value is thus subjective and different for each person for each and everything they may seek to trade.
I like Monero, I like Bitcoin, Ethereum, gold, silver ... They have value for me as they can't be arbitrarily created from nothing. There are limits and conditions beyond pure human will.