well if it's something to do in the world then yeah, it's content. The problem with grinds is that they need to have a point to them (for me at least). So, for example, a gear grind is worthwhile if you're wanting to raid. It's similar, psychologically, to leveling. You do the activity to get to a point where you can do some new content.
It's why I don't value piling up gold - I don't get any pleasure from simply having a ton of gold. Similarly, a person who has no intention of raiding or doing mythic+ dungeons probably will get to 825-830 level and see little point in going much further. Mats farming? Unless you like being the go to person in your guild for making things, eh.
It's why I'm pausing y sub to Legion - I don't raid anymore and I don't think we'll end up with a consistent Mythic+ group (and anyway, making content just harder isn't that interesting to me). This isn't Legion so much as it is me. When I raided I *loved* hunting down gear upgrades, getting a feel for how my character played in group content, etc. Now? Eh.