I have a large roll fed ink-jet printer (Epson 9600 Ultrachrome). I make very large prints for one of my clients, both of artwork and of photographic originals. If I get even a "hint" of lines, I go thru the printhead cleaning program and clear it up. The problem with Kiosks is that the equipment is basically unserviced for long intervals except for ink and paper. Also, I use a rip which allows me to do a 4x or 8x print What that means is the print head goes over the same path 4 times or 8 times (you choose which in the RIP). This slows down the printing but makes for a very smooth image.
I would have to say in regards RA-4 mini-lab printing, I'll bet that 99% of all RA-4 mini-lab prints are made with laser exposure, whether the original is film or a digital file. Now you might think this is a "bad" thing, but in reality it is a "good" thing, as the only way to keep printing services available for analog materials (film) is to be able to do the printing thru the same machine that does the digital. It is not now economical to have a separate optical printer/processor just for film in the average mini-lab. There is nothing inferior with this technology, it can produce excellent, first quality prints, IF the operator is skilled in running it. Also, RA-4 prints are far more economical to produce in regards raw materials cost, than inkjet or dye-sub prints are.