For the past couple of days I've been using Word 365, including the Editor Pane on an isolated machine - i.e. no network, not even an avian carrier connection.
Seems to me that having or not having Intelligent Services (IS) checked makes not one scrap of difference to the current Editor Pane functionality. I say
current because I'm wondering if... as they add functionality to grammar checking... they will do what Language Tools have done, make it a chargeable service - LT want $AU79 per annum for their latest and greatest... ouch.
One feature that does need Intelligent Services is, unsurprisingly, Word's Translation tool, if it's unchecked you get this
If the Editor Pane needed IS then it's reasonable to assume it would have a similar popup. Yes I did check every option in Settings, and I did test most conditions.
BR