Sounds like they’re referring to characteristics of TempleOS that may have suited the original goals of the Raspberry Pi, which was to be a tinker-friendly device for audiences like school children.

Some people lament the fact that it simply ended up with a plain, general purpose Unix-like, rather than something more low level and immediately direct (as in, drop you to a BASIC, not necessarily assembler), ala Commodore 64.

The peculiarities of the author aside, a live TempleOS was able to have its running code modified on the fly, and allowed direct low level access to what was under the hood in perhaps a more interesting hacker-ish way than your typical Unix clone/descendant.