When assets such as currencies, a bank account, a business, real estate, or other valuables are put into a trust, you refer to it as an “exchange” rather than a “gift” or a “transfer”. Why is this, and what does the trust give in exchange?

The trust gives Units of Beneficial Interest. These are like shares of stock in the trust. A settlor (or anyone) can certainly “donate” valuables to a trust, without any units being received in exchange, but that sets up the donor for being questioned later. If any liability were ever to come against the donor, the claimant could challenge the gift as an avoidance of obligation. But if the giver receives Units of Beneficial Interest from the trust in exchange for the asset transferred into it, then it is perceived as a lot more normal and acceptable to others. Exchange transactions take place by the millions every day all over the world. That is ordinary commerce.