I think you're right, in multiple meanings. :) To unpack your potential #vaguejoke (a useful heresy if there ever was one):

1. It could be huge, because it means less of a dependency on Javascript. Javascript has become the de-facto language on the web for... well, everyone knows why. But I don't think it's great that it's the only real option.
2. It could mean that servers and clients could share code, without being Javascript itself necessarily. That vision is partly what lead me to explore Guile, amongst several other things. That could be huge for client-server frameworks in any non-JS language which can manage a nice export to WASM.
3. It could be huge in terms of the size of executables! :) Many web pages now take 25 or more megabytes just to load these days, which is kinda obscene. That's probably going to get a lot harsher.
4. It could be huge, as in terms of pushing for more of an "executable web" over the "document web". Sadly I think this may be more huge for proprietary software than free software, for reasons that are long to get into (but it doesn't, in theory, have to be.)

3 sucks, 4 might suck, but I think 1 & 2 are enough of a win that I'm pretty happy about it.