Textures would be an issue with the pen...
thankfully that isn't the case with the stylus and applying textures in program.
But a Blending prob with 16 million shades hues and colours?
I used to use prismacolors as a kid...and looking back then to now...I personally have no prob with either oils, pastels nor penabled convertible tablet pc programs getting fine detail or blending...and concerning penabled illustration work with comp...the level of extraordinary depth and fine work is frankly miraculous in my humble estimation.
expensive?
hmm...well...right now 69 bucks as an early adopter with extras ...for the stylus. Over $100 for 2...
It's less than that for early adopter for the pen...it was just over $35 I think....I glanced at the price briefly...It could be more...but it wasn't over $50.
Affordability is purely subjective to what's in a wallet...and the "need" for that particular thing.
Anyway...
I do understand getting into "the zone"... with particular methods and tools...and feeling more comfy ...it takes me some time for my hands to get comfortable with new styli ...or brushes...or carving tools... for that matter.....especially freshly purchased tools with new or radically different physical design modifications.

I used to be a classical purist back in the day when it came to drawing painting and sculpture....I was a techno-artistic Luddite ...
which extended into the rest of my life with tech...I learned coding back in the grand age of the 1st comps. ...the vic 20...the comm 64...
but I pretty much abandoned tech...for about 15 years...just wanted to make stuff...not sit at a comp. ...until the late 1990's and I saw the writing on the wall...the fact that every aspect of personal, social, and business life was becoming tied to comps. ....My enforced anti-tech solitude would not be sustainable in our civilization....and knowledge meaning power and freedom...what option but to learn ...eh? ....so I had a hell of a sharp learning curve to deal with.

And of course...slow and sure... the artistic techno-innovation "goodies-bag" ...just kept getting better and better...to the point it had me drooling with wanting to play with the tech.
Tell ya it was a trick getting used to using haptic gloves and virtual (glasses) environments to play with 2 and 3d design, drawing, painting and sculpture....it was only once I started using resistance feedback haptics (where when you touch or handle objects in a virtual environment that you can sorta "feel" resistances...weights and pressures ...in a very weird kinda way. Its like nothing else ...it's hard to explain how it "feels"...anyway...) that I found the artificial environment more comfortable....so to speak.
So now ..for myself ...where I used to have a revulsion response especially to tech and art combined....now I have no prob enjoying it. A tool is a tool ...I enjoy my carving, instrument making, brushes, paints and box of sketching charcoal and my graphites as much as my stylus, haptics, virt. glasses and environs. Just a matter of what I feel like that day or days and what the project is. I'm simply happy for all the options at our disposal nowadays.