Some good points. I agree everything *should* be ok, and for a system not running a lot of different programs, no big deal. My comments are based on years and years of corporate experience dating back to before Windows. We have some apps that plain will not run (vendor actually warned us) on win8.x, and some won't work on 10 for a few months, even though they're solid on 7. Not necessarily Window's fault, but something changed enough to be an issue.
If I had a computer running JUST BI, then yeah I'd have no issue upgrading to 10, but apps aside, I have seen stability issues with many major Windows releases.
XP was solid, but not at first release. NT4 wasn't stable until after a couple service packs. And Vista was a train-wreck until SP1.
So, yeah I'll still recommend waiting at least for the first round of patches for any computer that needs to be stable.