I was watching memory usage today, and I found that I got the same benefit by simply minimizing the Roon window (more intuitive for a user than closing it).
After launching Roon Remote on my Mac and immediately minimizing the window, the memory usage stabilized at around 325MB. When I reopened the window, the memory jumped up immediately to 650MB, then leveled out around 500MB. Then I browsed the Qobuz library, queued up a couple of albums, started play and minimized the window, and the memory usage remained very stable around 600MB. At times I saw the memory rise temporarily (up to 660MB) but it would drop back down to about 600MB. When I was leaving the window open, it would steadily rise up to 2 GB or higher.
My suggestion for Mac users is to keep the Roon window minimized whenever you are not actively interacting with it (use Command-M or click on the window’s yellow button).