Money is a cheap way to translate unlike objects. Cows to art, labor to goods. Green to triangle.
Money (or something) will always exist, because it is a needed lubricant for transactions.
[0] https://en.wikipedia.org/wiki/Fungibility
So it's only useful for as long as you have the need for transactions.
Which you will always have some need for, because resources aren't infinite, real estate isn't infinite, services aren't infinite, etc
Money is a cheap way to translate unlike objects. Cows to art, labor to goods. Green to triangle.
Money (or something) will always exist, because it is a needed lubricant for transactions.