Astonishingly naïve
One is that 'it will drive the problem underground.' Will company directors really knowingly break the criminal law?
I have to wonder if Mr Martin has ever followed the news.
Forbidding payments is a useless gesture. It's security theater as legislation.
It does not significantly alter the motivation to attack, because attacking is extremely cheap and largely conducted by affiliates who are strongly motivated. It does not significantly alter the motivation to pay, because the whole point of ransom payments is that they're difficult to trace.
And as the entire ransomware industry becomes increasingly automated — which is more or less inevitable because of the economic advantages — it won't matter even if all payments were prevented, because the bot armies are not sensitive to the rate of return.
As always, this particular line of argument only demonstrates which "security experts" are any good at security thinking.