When I've had storage units and spent time there, and saw open doors and what people had in theirs, I stand by my take.
The whole point of the article posted above was that it's a bit weird how numerous and prevalent self-storage has gotten in the US.
Aka, trash by proxy.
Best to look up what people actually need. There is a lot of this junk we collect that just gets junked by the donation groups turning into a cost center.
If you move often enough within a small radius, you will highly value your storage unit. It's not necessarily just a place for junk. Many people rotate their things when their apartment lease is up or even seasonally. If you live near water, you might even store a boat. Many facilities also offer RV storage. Personally, when I had roommates I would keep my most important stuff in there instead of at home.
The attacks against storage units are engagement bait for nerds about a non-story.