It takes me about 15 seconds to boot my computer. But do I need to start the computer each time I do something on it? No, I leave it on.
Similarly goes for other things you use but takes "too long time" to open, leave the thing open and you just have to switch windows to access it.
And if you think Obsidian is a note taking app, then yeah, it's not the right tool for you, continue using Vi/m. But once you grow out of it, you'll need a knowledge base instead, and for that, Obsidian is lightweight.
You may also use any other note taking app as your default brain dump and use Obsidian as your editor tool to work your notes afterwords. Just for note taking anything would work its markdown/text. Where obsidian wins is backlinking information and all the wonderful community plugins that's been appearing.
:wq