Their press release actually says electric atlas is more powerful. Though I wonder if that's higher peak torque, and not so much explosive power required for jumps. A commercial robot doesn't need to do parkour.
Here is a quote from Ben Katz [1], who wrote a dissertation on building the mini-Cheetah at MIT, before joining Boston Dynamics:
"The hydraulic legged robots from Boston Dynamics, starting with Big Dog, have
set the standard for the performance capabilities of modern legged robots. Hydraulic actuators tend to have high force density and high robustness to impacts, as impact loads are distributed over the large surface area of the hydraulic channels, rather than, for example several small gear teeth. Another compelling reason to use hydraulics, especially for high degree-of-freedom machines, is the relative ease of adding high-force degrees of freedom. For an electric motor driven robots, each actuator needs to be sized for its peak performance, which makes building systems with many degrees of freedom needing high peak power and force at all the joints (and especially at
distal joints) very challenging. With a hydraulic system, it is easier to build high-force distal links (ankles, wrists, fingers, etc) without adding significant mass and inertia to the limbs."
