Used tubes a lot for salmon, of course. Also for trout and sea trout. (We don't have bass here). Plastic tubes, at one end of the scale, are usually easy to cast. Go to the other end of the scale and a 1" tungsten tube feels more at home on spinning gear. How difficult it is to cast depends on the tube and what you are trying to cast it with. For tippet judge it by the weight of the fly (stiff enough to turn it over) just as with a fly tied on a hook. Don't forget to include the hook when making your judgement. A plastic tube with hook will not need any more leader than a fly tied on a hook of similar overall size.

One great advantage is that, when playing the fish, the tube rides up the leader, saving the fly from damage by the fish's teeth.

Cheers,
A.