If you want an computer that you can wrap around a pencil, I bet it could be done simply using a very small conventional silicon chip embedded in a flexible medium. Perhaps some of this technology could help with interconnections.
Interpreted BASIC was the only thing most end users had on those computers, for quite a few years, until Turbo Pascal and Think Pascal/C changed everything.
Professional software was written in assembly language but at the start of the revolution most of the programs that people wrote themselves, or that you saw printed in magazines to type in yourself, were in BASIC.
It was fast enough for many tasks.
It makes no sense to compare the execution speed of the output of a modern C++ or Rust compiler on one architecture to a BASIC interpreter on another.
Of course this doesn't alter the point about being as fast as the BASIC that early PCs came with, the only thing most end users had to write their own programs on them until things such as Turbo Pascal appeared (November 1983).