Tauri makes it easy to port web apps to desktop without sacrificing much of the performance. It uses system's built-in webview rather than plain chromium, so there may be slight difference between platforms.
The sandboxing is kinda necessary, since you're still running a browser in the end, which can be easily exploited if done improperly. The explicit filesystem access ensures that even if it all goes haywire, only a restricted region of the filesystem endures potential damage, instead of an entire filesystem.