Drum scans are generally the best method to scan transparency film. Good operators can also do well with color negative film but this is not as popular, I think the software does not do great color conversions but again, it's all up to the operator.
I wouldn't say it's dying off exactly, but these scanners are no longer being made. So people still doing them are basically keeping old computers and parts alive. It's also a very involved and somewhat ridiculous process. You have to manually wet mount the film into these spinning drums. Then the scans themselves take ages.
If you have a really fabulous photo made with Velvia and are planning to make a 60" print, yes it's probably your best option.
If I were to upgrade my systems to rival drum scans at very large sizes, I would replace my S1R scanning set up with a GFX 100, which can make a 400mp pixel shifted capture. But some people who love drum scans are never going to be convinced that anything else will do.