If money grew on trees it seems that could result in vast monocultures, with ruinous environmental impacts. I suppose it depends on currency. If the money tree produced only Iranian rials or Venezualan bolivars, we’d likely consider it a noxious weed.
On the South Pacific island of New Caledonia, there’s a rainforest understory tree that doesn’t bear money; it is money. More or less. The milky sap of Pycnandra acuminata is 25% nickel, the exact same percentage of the shiny metal that the US has been putting in its nickels for the past 155 years (for perspective, nickel ore of 2% is high). To me, the fact a tropical tree can bleed money is nowhere near as strange as the fact that the thing is alive at all, given that even small amounts of nickel – we’re talking below one percent – will kill most plants.