I think your hunch is on point, I think because the author conflates running time of a busy beaver with benchmarks of programmatic coupling and cohesion.
Busy beaver algorithms are single-purpose programs. An eCommerce website is layers upon layers of interrelated modules and functions.
I get where they're going, reducing a problem space down to its simplest representation is ideal. I just don't on first pass understand how busy beaver accomplishes this.
In a 2-symbol TM, there are at most two outgoing edges in a state. If you remove the self-reference, you're left with just one. That seems to remove too much of the hidden complexity.
I suppose the thinking behind it is "a loop is not spaghetti code", but a loop in higher level language rarely translates to a single state moving to itself.
OTOH, it's possible to write spaghetti-code in a system that only has while loops and if-then-else by simply having very complex conditions, and modifying the variables on which they depend at seemingly unrelated points in the code. After all, both are TM complete.