I sailed on a lot of steam ships for the simple reason that the U.S. kept them long after the rest of the world switched over to diesels. We were still building them until around 1980, and a lot of the old World War II vintage steamships were still operating well into the mid 1980s. Farrell Lines' container ship S.S. Argonaut, which was built in 1978, was retired in 2006. I believe that Horizon Lines may still be operating a few 1960s and 1970s vintage steam-turbine container ships to this day.
Diesels have advantages in initial cost, size, fuel consumption and manning. Most modern marine diesels have unmanned engine rooms, which means that there are no engine room watch-standers, and the engines are monitored at night from the bridge. However, that doesn't mean that the engineers are idle. It simply means that they spend each and every day performing maintenance, and there's a lot of maintenance.
All the steamships I've sailed on required 24-hour watch-standers, even those that were "automated". However, they were infinitely more reliable than diesels. One five-year-old diesel ship I sailed suffered more engine casualties in four months than ALL the steamships I've sailed on COMBINED. I've often heard it said on those old team turbine ships that the hull would wear out before the engines did.
Steam turbines are much smoother-running than diesels. They can also be reversed at any time, which diesels can not. On Farrel Lines' three diesel-engined "E-Ships" container vessels (Endurance, Endeavor and Enterprise), you could not start the engines astern if the ships were making headway of more than about four knots. If you tried then the engines simply wouldn't start. That sort of thing can be embarrassing when maneuvering into port.