Until it doesn't. A few files in iCloud drive just stopped syncing a handful of times. Is it a network issue? A temporary glitch? Should I restart the computer? Or just wait a little? Nobody knows!
I switched to Syncthing for syncing files. It also fails sometimes. But it shows a clear, actionable error message when it fails (eg: file name contains characters not supported on target device). And there's a button to manually trigger a sync in case the file system observation didn't work.
With iCloud it's always a surprise. Is it going to sync? Probably. When? In the next minute probably. It's been 5 minutes, is there a way to sync right now? Try restarting the computer, maybe that'll fix it.
The unspoken truth. Yes, you may get more debug output in other ecosystems but there are going to be mountains of bugs and a kludge of workarounds to get “seamless” integration.
Can this particular problem be solved better now? Yes. Can every other cross device integration be solved as well? No way!
The pain stretches across software and hardware.