I’m not sure which NanoPi you’re looking at; the Core Air is not quite 2x the price ($32 vs. $18) of the VoCore and only a bit wider/longer, and similarly thin. Also, as you mention it’s in an entirely different class w.r.t. performance, if a bit power-hungry compared to newer SoC designs.

Neither one is going to compete with a cheap Atmel or RISC-V MCU in cost, but on the flip side the NEO Core et. al. can run a web server, Docker containers, or a NodeJS app under modest load vs. needing everything rewritten in very tightly-managed C. :)

The nanopi neo lts is $16 https://www.friendlyelec.com/index.php?route=product/product... and I have found it to be pretty good.