It is actually not the fact that V8 in context of Sciter alike use cases will be faster.

Consider this statement:

    document.body.patch(<body>Hello world</body>);

While in browser, in case of ReactJS, you will run that patch() (reconciliation procedure ReactDOM.render) with JS VM speed as that algorithm is implemented on JS/TS.

The whole point of Sciter is in its embeddability - you can add native objects of your app callable directly from script. Check this example of native object: https://github.com/c-smile/sciter-js-sdk/blob/main/demos/int...

So you really don't need V8 JIT infrastructure to achieve max performance - just add native objects when needed.

UPDATE: Now I have read the linked article, here is the reasons (copied from the article):

API and integration principles are close to what TIScript uses – it took me just 1 month to add QuickJS to Sciter core. And 4 months more to expose HTML/CSS runtime to JS.

Relatively compact implementation – QuickJS is slightly more fatty (by 100 kb) but still in acceptable range. For the note: full version of V8 is about 40 mb – 5 times larger than Sciter itself;

Liberal MIT license. Sciter cannot use GPL/LGPL code – many customers expressed this requirement;

Readable source code. Well… almost readable.

"Relatively compact implementation – QuickJS is slightly more fatty (by 100 kb) but still in acceptable range. For the note: full version of V8 is about 40 mb – 5 times larger than Sciter itself"