You might not have a choice. Sometimes even seemingly trivial APIs/features like SVG, flexbox, or audio/video behave slightly differently in different browsers, and it's easy to sink a lot of time into debugging these differences. I'm not saying the effort isn't ever worth it, and it's certainly better now than it ever was in the past, but I think you're underestimating the amount of work it takes to properly support a complex web app across all modern browsers.
With that said, if you're just using web technologies to throw together a UI to slap on your native app that does all the heavy lifting, then sure, maybe using something like Tauri is worth it. Even then, it might not be worth the QA burden of having to test all UI changes against every supported platform, and then the support burden of getting platform-specific bug reports.