A lot of work has gone into reducing the performance issues that have plagued WebAssembly in regards to making JS calls (especially when working with the DOM). Efforts seem to be focused on making WebAssembly more than a memory-siloed thing, but rather a viable alternative for anyone wanting to work mostly within the confines of WebAssembly.
One of the areas that WebAssembly has the potential to be used in is gaming. A port of Doom 3 into WebAssembly has proven to be a huge success. Figma famously made the early move to use WebAssembly in 2017 and saw huge performance benefits.
Going forward, you’ll not only see games take advantage of WebAssembly, but another promising area where I believe you’ll see some WebAssembly innovation is blockchain. Imagine, a blockchain running inside of your web browser which could be used for building decentralised applications or as a stand-in for traditional databases.
I also envision web frameworks and libraries using WebAssembly for their virtual DOM implementations such as ReactJS. Imagine if the dom-diffing algorithm used for the Virtual DOM was moved inside of WebAssembly, freeing up the main thread for crucial UI tasks and ensuring smoother frame rates?