Switching from 170W to 140W can be a wise move when we only look at the entry-level and mid-range RTX 2000 and Ultra 7 CPUs. However, I seriously doubt that a tiny USB-C port could handle the much more demanding RTX 4000 and 5000, as well as Ultra 9 CPUs.
The latest model ships with a 140 W USB-C AC adapter instead of the 170 W adapter that shipped with last year's model. Fortunately, performance has not been negatively affected.