The main subject/ interest was that gcc 4.7 is the LAST compiler that can be build with only C and without C++. Personaly I dislike how "they" did it (too many tools to compile/trust first, like MAKE).
It should start wit the MINIMUM packages. A normal (or security concerned) singular person could NOT have enough time/knowlegde to AUDIT mastodonts (huge pile of code) like KERNEL or GCC compiler. What remains is then the basic LIB (libc) -- or musl libc (is smaller). But even those libs are big to audit. Plus the kernel compilation could recently ask for not-necessary auxiliary tools like make/perl/bc/rust whatever.
So the only piece that a common user could control is the SHELL (busybox or toybox). This was the key to boot-strap a NEW linux (a new kernel RE-compiled from 4 packages: minimal old KERNEL + gcc + libc + shell). Rob Landley at least provided this base, build without using neither perl, nor bc, etc. He did not used LFS (linux From Scratch) method. So he reduced attach surface (numer of initial tools) to build a trustfull base. AND provided to all of us the tar-ball (with kernel + root + compiler) to start our journey from scratch.
Because if the initial tools (lets say perl) is "compromised" then the initial build base is then compromised. Yes, I know GCC will try to compile itself again from itself as a safe check. It does not matter if is busybox, or toybox, or anything else. It all resumes to: (you) trust (them) the trusty. The smaller the base tools -- the better. With "rust" tommorow in kernel, gcc/lwm depending on C++ .. just pray/hope that all will still be good (I do not).