Me neither, but for a different reason. I use the Scriracha for Asian dishes or at the table, as it has a great taste.
For Cajun you want Cajun hot sauce, and for Mexican, I usually use the juice from pickled jalapenos (and chop some up too)
The bottom line is, if you don't go crazy, all those sauces/juices impart a specific flavor without adding a lot of heat (unless you get crazy with them) You certainly can't take it back out.
Ground Cayenne pepper will make it hot, but doesn't have much flavor benefit.
I disagree. Cayenne pepper in soups and other dishes is a flavor intensifier, much like salt is. The trick is to use just the right amount. It has to be below the point where people can identify it in the dish.