you mean to use them as a small wacom touch tablet but portable ?
just using your finger or stylus to draw simple 2d strokes is easy enough to code and optimise but having a nice 3d stroke implementation such as what wacom is using requires years of RND. they have a minimum of 1024 sensitivity level combined with advanced 3d stroke-sensing motions for their pro pens. also the feel of using the classic wacom tablet with no screen or just touch is very much like the feeling you get from pores on real paper (at least on their new models). that’s why i don’t use the modern draw-on-screen directly wacoms because they don’t provide real friction.
also beeing limited to 8 bit iLUT on the open-source driver implementations of gpus VCGT (video card gama table) means severe color-banding in non-properly color-managed applications even if the display-panel is properly color-calibrated/profiled.
let’s not get too carried away and just enjoy this for what it is … a handy note-taking app with touch/stylus support for simple 2d/strokes. if it get’s enough love it can be used for black-n-white simple hand-drawn sketches or really awesome Van Gogh style painting at low resolution