Earlier quoted context omitted.
I’m not sure what you mean by “illustrate when qubits have become entangled”. Can you explain?
Entanglement is fundamental to QC, right? So in order to be a useful visualisation of an algorithm, a pictorial representation like a circuit should give some intuition to aid understanding such as: which qubits can potentially be entangled at a given stage in the circuit, etc.
Why is this (or the demo I linked to earlier) not a satisfactory representation?
https://qph.fs.quoracdn.net/main-qimg-1ab704621d3c845630ab6f....