This sounds amazing, but at the same time, I am concerned about the rain forest. Obviously more economically useful crops would accelerate repurposing the rain forest. Maybe the world would need to subsidize Brazil more to keep the rain forest? And could Brazil be expecting more subsidy with this development?
I remember being asked in elementary school to help "buy a piece of the Amazon to stop it from being cut down". I mentioned this years later to some Brazilian friends, and they found it amazing, saying first that it almost certainly wasn't a specific plot of land, and second that enforcement of property rights and anti-poaching laws in spread-out rural areas has been spotty, and also hindered by violence and corruption.
So I guess it's a thorny question, if someone in Brazil accepts such a subsidy, how that ultimately translates into physically stopping people from making illicit uses of Amazon lands.
Edit: In theory, stopping an illicit farm (which takes time to grow and has to be tended and harvested) would be easier than stopping someone with a pickup truck and chainsaw from just grabbing a bunch of trees for lumber. On the other hand, the U.S. has spent tons of money trying to eradicate poor people's coca farms in the Andes and it doesn't seem to have had the level of success the government hoped for (https://en.wikipedia.org/wiki/Coca_eradication).
Meanwhile, some people are apparently still maintaining wildcat marijuana farms on U.S. Federal lands. Wheat farms aren't as profitable as coca or marijuana, but even suppressing certain kinds of farms in remote enough areas seems like it can be non-trivial!