The other feature to visit from Deer Creek Bridge is a nearby hot spring, maybe a hundred yards downstream from that crossing. It's at the river's edge, and as far as I'm concerned, not terribly appealing in terms of bathing. It's shallow, kind of yucky looking, and smells strongly of sulfur. Now, again, IMO, this doesn't make it less interesting or worthy of inspection, just not a hot spring I'm inclined to get into, physically.
On the other hand, I know a number of people who have, and they enjoyed it. Whatever floats your boat. However, if you're the sort of person who's discomfited by having a bunch of geology types come gawking at the spring while you're soaking in it nude, you might want to think about some sort of bathing suit or rethinking your choice about where to stew. This is a well-known, easily accessible, and fully public location. Strangers may show up at any time... clothed or not.
While hot springs in and of themselves are uncommon enough to be intrinsically interesting, this one likely marks a permeable region along the western fault (system?) of the High Cascades Graben. There are a number of hot springs along this trench, some of which are developed, others, like this one, just warm puddles in the woods.