Great question about self-storage (ss) being a business or a real estate play. I think the same thing applies to any real estate though. Whether it commercial office space, apartments or single family the question really comes down to whether you are in the landlording/operating business or the property owning business. If you're the landlord, that's a whole different business than if you're an owner.
Yes the property manger is a large expense item for many facilities but it's just that, an expense item. If you are in the owning business then a deal isn't a deal unless it pencils with professional property management, no matter what sector it's in.
The great thing is that technology has come to the ss industry with kiosk systems which integrate with the management platforms and security systems. Now you really only need someone to walk the property to make sure it's clean and undamaged; leasing, collecting rents, locking out delinquent tenants, even selling locks can be handled by automated systems. Many platforms also provide live chat/phone banks to answer questions as well as providing SMO online advertising and marketing along with lease management systems that optimize rents.
With those systems in place you can truly be in the self-storage owning business.
Interesting also that several people have mentioned the land banking strategy for ss. Back in the '80s my mom was on the board of a privately held real estate company and pitched the idea of acquiring two ss facilities located in Bellevue, a suburb of Seattle. The land bank idea was part of her pitch back then too. She couldn't sell the board on the idea and since then Bellevue has grown into its own urban center with 2MM sf of Microsoft office space among many others but those two single-story, unheated ss facilities are still there... because they cashflow like mad. Eventually Public Storage acquired them... who also used to pitch the land bank idea for their limited partnership deals back in the day before they went public.