i'd guess adafruit's intent is to allow young students to get started without having to grapple with the rather intimidating and dicy plays going down to bare metal programming and compiler tool chain. circuit python can come pre-installed on the boards adafruit sells, and blinking a led is just issuing a command.
this compares quite directly with Lua
http://www.eluaproject.net/
and even perhaps go
https://embeddedgo.github.io/
they are useful in this case and also useful in situations that don't after all needs to get down to 'bare metal' to get the results
a problem though is that the overheads means that it couldn't squeeze into an mcu like stm32f103c8 with 20k sram
accordingly forth works, and is the leanest of all the interpreted languages that runs on stm32f103c8 and did many use cases
https://jeelabs.org/article/1608d/
i've not really explored it but had to admire the attempt, it is really cool to have done that
back to c (and maybe c++) and maybe even down to 'bare metal' (i.e. messing with registers)
assembly is simply too unreadable for a program more complex than a blinky, short of commenting the codes properly
even a blinky would be unreadable if it isn't appropriately commented as there would be initialization and such.
c and best of all c++ is good as they allow all that structures and procedures to be expressed
c++ 11 in addition helps avoid a lot of cases needing to use pointers by using references instead. this has prevented quite some problems messing with pointers. it is so easy to swap pointers and forget what links to what. that makes for the most fluid and flexible programs that could be near impossible to debug
c/c++ 11 etc has made 'bare metal' development looked 'too easy', i'd say the compilers has reached an extent they are technologies in themselves
that has enabled all these development on arm micro controllers with barely 20k of sram, and hardly more flash. and some with even less
and because c/c++ is so lean and expressive, it makes even 'arduino' works pretty much like a little 'os'. literally and with a little more resources they made apps on smart watches and such happen in under 1 M of sram and flash, graphics, apps, games, etc. and no less toggling hardware at real time speeds