I had Windows 8 RMT Enterprise 9200 installed and activated (during online of KMS-server), but had to re-install because of non-working apps (see thread Windows 8 Apps not working anymore?. So I know the difference between being unactivated (start first installation), activated (after KMS was discovered) and inactivated again (after re-installation). I didn't try to activate again, as I wonder if activation had that much benefit. I can see more benefits for being in notification (not activated) status: 1. Not the need to reactivate after 180 days. 2. Not dependent of present of even absent KMS-servers. 3. Windows will run "forever". 4. As far as I understand: also no problems after the official release of Windows 8. 5. No problems after re-installations. 6. The same functionality as the activated Windows. There is however one downside: the options of Personalize under Change PC Settings can't be changed, although most of them can be altered by e.g. registry tricks. But for me these options are not important to change. If I overlooked facts that it really makes worth to activate, please let me know.
First, at least some of your numbered points are actually merely strongly believed or speculated based only on what's been observed so far. While I personally hold the same belief so far, I also retain enough objectivity to admit the possibility that things will not continue as "smooth" as they have forever and ever while remaining inactivated. One other benefit of activation other than that mentioned is whenever "Genuine" status is required for various things, such as downloading some files from Microsoft (I'm assuming they still do that for some downloads - correct me if I'm wrong). Maybe a future update, such as an updated Windows Defender or a newer version of MSE which is allowed to officially replace Windows Defender, will require Genuine status in order to install. Not needing to run hacks to get rid of watermarks, both on the Desktop and the post-three hour Explorer one, would be nice.