My bigger snakes go outside and "play" all the time. Some of my smaller ones don't, but only because I am afraid they may get away from, due to small size and the ability to get into small cracks, crevices, or holes that I may not even see.
But for my bigger snakes, playing in the grass and trees is a fun and stimulating experience. They sometimes get ants on them, or insects will fly over and land on them...but overall, it is aparrently an enjoyable experience for them. With all the new sights, smells, and vibrations, it seems to be "system overload" at first, and they freeze for a few minutes...getting their bearings, I imagine. But after a few seconds of cautious stillness, they start slithering around and exploring a bit...