I hate working with new programs. You don't have that problem working in traditional media either. If you get a new 2b pencil, nothing is moved around. Nothing is really particularly different. It may or may not have an eraser. It may be a slightly different lead value. But it's still a pencil. It will behave like a pencil. Art programs? There's no consistency. I found Photoshop far easier to manage than Krita, and the learning curve of trying any new program, be it Sketchbook Pro or anything else out there, would frustrate me to no end and I do not appreciate being barred from just having fun. It's more like each individual art program is its own media, and I just do not have the patience to switch and learn new media when that's not the point of what I'm trying to do. I picked up marker because I wanted to, not because my colored pencils expired, went out of stock, or had to be updated.
That isn't to say that I hate all digital art programs or that any other program can achieve the same results as another. Traditional media will almost never look like digital media, and digital media can only imitate the appearance of traditional media. MSPaint will never really look like Photoshop, although Photoshop has options to look like MSPaint. Digital is far more versatile due to its power to mimic.
It's just how programs behave that bother me. My broke ass who ain't got enough money for first month's rent at the end of July don't have the money to upgrade my old Windows 7 laptop to something that can handle big canvases and make digital art look good either--because it's not just the programs. The hardware and stuff that adds to the complication. With traditional, you have your media, and that's your hardware. Digital adds software as a middle-man. And boy, can that middle man screw you over.
All in all, I can have more fun with a mechanical pencil I found on the sidewalk that ain't got half an eraser left, a ballpoint pen someone dropped in front of the library, and old sketchbook, and it's so much less of a headache.
To top it off, there's no troubleshooting required with traditional. Pencil not working? Sharpen it. Pen not working? Probably out of ink. Scribble a bit and see if it comes back. Paper acting up? Stop erasing so much over that one area. Or maybe you got cardstock or watercolor grade paper and you're only using pencil. The reasons why things aren't working is usually obvious. With my tablet, however, sometimes I'll plug it in and the driver will do a test and it looks like pressure's working fine but Krita won't differentiate pressure and the hotkeys are messed up despite the fact that the driver says they're okay. Happens about 1 in every 20 or so plug-ins. I can't imagine a world where a pencil only creates different value on paper for no apparent reason only 19 out of every 20 times it's used, but with digital. Meh. That's just to be expected.