Dynamical systems theory as a metaphor in psychology: is it useful or not?
Like all models and modeling frameworks, the utility of the approach is often tied to how much it increases our understanding of the phenomena of interest. As summarized nicely by Smith &amp; Thelen (2003), there are developmental questions that are better conceptualized through the framework of DST than through alternative modeling frameworks due to the richly interactive and multi-causal structure of the phenomena.

You'll also find that applications of DST in Developmental Psychology are not just appealing to the metaphorical use of DST. There are rigorous mathematical uses of the tools of DST to explain developmental phenomena. One of the most cited examples is Thelen et al. (2001), who modeled the A-not-B error. There is a lot of similarly inspired modeling work being done throughout the field.