All 3 enhancements noted. Will be implemented in next release.
Update: The line shortcuts and line numbers will be in the next release. The side-by-side/split view requires a significant architecture refactor, so that one will take longer - it's on the roadmap but not for the immediate next release.
Electron came first and has a massive ecosystem. Most apps were built before Tauri was mature enough. Switching frameworks is expensive, so existing apps stay on Electron.
New projects are increasingly picking Tauri though.
Tauri is an alternative to Electron. Both are frameworks for building desktop apps with web technologies, but Electron bundles a full Chromium browser (which is why Electron apps use so much RAM). Tauri uses your OS's native webview instead, much smaller, much lighter.
Both are open source. The difference is resource usage.
Obsidian's default editor is barebones, you need plugins to get a usable experience. HelixNotes gives you rich editing out of the box: formatting toolbar, slash commands, source mode toggle. No setup.
It's also not Electron. Rust + Tauri 2.0 & Svelte fraction of the RAM, launches instantly.
Same philosophy though: local .md files, no cloud, no lock-in. If Obsidian works for you, no reason to switch.
The fact you need a guide to get a working Notepad and Paint back says everything about the state of Windows 11 and Microsoft.