The architect, Santiago Calatrava, is the same guy who was hired to build the structures for the Athens Olympics. That means the bridge gets worldwide recognition as a thing of beauty, and Redding with it. Plaudits have come from around the world, and that means tourism, unlike merely doubling the acreage in the park. If you do a Google Search on "Turtle Bay" + "Sundial Bridge" you'll get over 1,100 references, for "Sundial Bridge" alone there are over 3,300. I guess the word is getting out.
It's all part of Redding becoming a city, something that doesn't thrill me but is part of having a growing population. Museum attendance was nearly 53,000 people in its first five months. It takes time, but such things usually do pretty well for a community over the long run.
Time will tell, but if I were you and I cared about Redding, I'd stop slamming the thing and start looking for opportunities instead of dumping mindless bitching with no understanding of economics. That this thing is inducing over one third its cost in new investment in its first year is quite promising.