[namibj]

Remember that the companies producing them use rolls in a printing press. This also allows for 3-d effects by applying e.g. resin with a deep-cut negative on the roll. The substrates lending themselves to this use are also probably different between direct digital printing and use of such a steel roll.

[King-Aaron]

So a lot of offset printers will be like that, however if you can find a company that operates a flatbed such as a SwissQ, you can actually print 3d effects with layers of resin. While it's still a roll-to-roll process, because it's dragged across a large flat table while printing they can do some interesting things.