In my experience I get grumpy and am not as fresh, if I sleep longer than 8 hours.
For weekends or holidays I use it like that, then the duration of sleep is more important than the waking-up point. I could do rough math in my head and then look at the “Next Alarm in…” but like that its so much easier. One click and its set.
I also have three more alarm shortcuts to set it to the three different trains I take for work.






Not really. I personally am almost more interested by how how much an app locks you in. With obsidian its not at all imo, as you have all your data in human readable .md files. Its more or less just a very sophisticated amd well made text editor.
It would be trivial to edit your notes if obsidian will ever enshittify, so they wont, as they know exactly that.