with respect to software that doesn't need to be efficient, sure, there are lots of things that are usable without being efficient. but in rek and devine's notes on working offgrid, which are part of the background motivation for uxn/varvara, they say:

> Computers are generally power-sucking vampires. Choosing different
software, operating systems, or working from machines with a lower
draw (ARM) or even throttling the CPU, are some of the many things
we do to lower our power requirements. The way that software is
built has a substantial impact on the power consumption of a system,
it is shocking how cpu-intensive modern programs can be.

so uxn/varvara is not intended for software that doesn't need to be efficient, very much the contrary.
so, from my point of view, the fact that logic-intensive programs running in uxn consume 20× more energy than they need to is basically a mistake; rek and devine made choices in its design that keep it from meeting their own goals. which isn't to say it's valueless, just that it's possible to do 20× better

what i mean by 'logic-intensive' is programs that spend most of their time running uxn code doing some kind of user-defined computation, like compilation, npc pathfinding, or numerical integration. if your program spends most of its cpu blitting sprites onto the screen, well, that's taken care of by the varvara code, and there's nothing in the varvara definition that requires that to be inefficient. but uxn itself is very hard to implement efficiently, which creates pressure to push more complexity into varvara, and varvara has ended up fairly complex and therefore more difficult than necessary to implement at all. and i think that's another failure of uxn/varvara to fulfill its own ideals. or anyway it does much worse according to its own ideals than a better design would

how much complexity does varvara impose on you? in https://news.ycombinator.com/item?id=32219386 i said the uxn/varvara implementation for the nintendo ds is 5200 lines of c, so roughly speaking it's about 20× more complexity than uxn itself

and that's what i mean by 'and it's not that simple'. in the comment i linked above, i pointed out that chifir (the first archival virtual machine good enough to criticize, which is a somewhat different purpose) took me 75 lines of c to implement, and adding graphical output to it with yeso required another 30 lines of code. you might reasonably wonder how much complexity i'm sweeping under the carpet of yeso, since surely some of those 5200 lines of code in the uxn/varvara implementation for the nintendo ds are imposed by the ds platform and not by varvara. the parts of yeso used by my chifir implementation compiled for x-windows are yeso.h, yeso-xlib.c, and yeso-pic.c, which total 518 lines of code according to either sloccount or cloc.

still, uxn, even with varvara, is much better than anything else out there; like i said, it's the first effort in this direction that's good enough to criticize

i don't understand what you mean about octo vs. decker but possibly that's because i haven't tried to use either one

you definitely can't deal with a 4×6 font on the ls027b7dh01 display i'm using. it's 35mm tall, including the pixel-less borders, and 240 pixels tall. so 6 pixels is 0.88 mm, or a 2.5 point font. even young people and nearsighted people typically need a magnifier to read a 2.5 point font.