Perhaps a couple bags of grass fertilizer.
Perhaps hauling the kids stuff to/from college.
That's about it. The rest of the time they struggle to park them in strip mall parking lots.
I have hauled multiple loads of mulch, other landscaping stuff and animal feed when helping my parents at their home/small farm in the summer.
I have moved in and out of college dorms/houses with all of my belongings (including my TV, kitchen equipment, lots of electronics lab equipment that I purchased to resell as a side-gig in college...)
All using a 2005 Buick LeSabre.
If you need literal truckloads of bulk supplies often enough to justify owning a truck then congratulations you're probably running a landscaping company or something so you might need a truck.
And that's clearly not what I'm talking about at all in this thread.
But what's nice about having a truck now is that I don't really have to try. I can just plop most things in the bed and go. You're right that it's not 100% necessary, but it's a great tool when you need it. That's one of the reasons they're so popular where I'm from (Georgia).