Man, you can tell this was written by HD, it's actually pretty funny. "Like Denim fabric, Denim paint will burnish or mar with age and use,
thus adding character and personality to the finish of the motorcycle." Got to love the positive spin they're trying to put on flawed paint. It sounds like it will have the same effects of flat black. Once you drag your fingernail over it, that shine mark stays forever. I suspect the Matt finish of the denim will be a little hardier than flat black though.
I'm painting my Wheels, Tanks & Rear Fender with a similar finish this winter. But due to upkeep, I'm going with a 2-stage paint. That will be a simple black base coat covered with a Matt finish clear coat. It's easy to care for, won't mar, and holds up for years. Plus that HD denim Black is way over priced. You can do a Base & Clear Coat for about the same cost.