I did a tour of one outside of Dayton, OH about a decade ago when they were finishing up the rebuild. The university system -maybe the state?- was turning a few of them into underground museum storage. They had cleaned up the water and mould, made some shelving and built floors and even a clean room for books, old furniture etc. They found it was easy to climate control the underground area, keep it safe from the weather and keep looters and other types away.

They did a few tours before they finalized construction and did the last climate control before there were any items in the place. Each floor of the silo had 3000 usable square feet or so, and each level was 15 feet high; if I remember correctly there were seven levels. It was neat to say you've been in a missile silo, but other than that it was kinda dull, honestly. And they had issues where the silo was so deep that they needed to create a special high capacity sump systems to pump water up the 150 feet or so to the surface.

I did see people talking about using these things as off-site data centers, emergency backup and recovery sites and other "high redundancy" sort of hardened facilities.

But still, there are some out there no too far from civil society that it is fun to dream about. And most of them come on acreage that you can turn into farm to be self sustaining. Build barns on top of the old silo entrances to hide the nature of what is underneath, deploy solar and the batteries from Solar City, run a fibre connection and stock the place with food and you got a bunker that you can live in for years.