I think they were just pointing out that software architecture will usually make a much bigger impact on efficiency and energy usage than language choice

A bloated app is wasteful no matter what language its in

Ah, okay, that makes sense :D I agree

It highly depends on what the use case is.

For most use cases JS is still more performant than WASM unless you're doing a lot of very heavy number crunching which the vast majority of WebApps aren't.

Browser vendors have done a ton to make JS fast.

> WASM is more efficient than JS...

Last time I checked it wasn't. That's a few years back. I would be really happy if it is now.

WASM does not have native access to DOM for starters.