Yes. Using Stryd indoors is a great way to capture running power as well as pace and distance. Stryd does not rely on GPS, and can be used in any environment to measure distance, pace, power and all other metrics.
An additional benefit: Stryd will report true treadmill pace and distance.
We have found that most treadmills have a difficult time of keeping a consistent, accurate pace when a runner is on the machine. Therefore, it is difficult to know what you are really getting out of the workout! Stryd's motion capture technology tells you what is really happening so you can make treadmill running as useful as outdoor running.