>Sure, but an equivalent conventional high explosive would have likely killed all those 1,000 people, wouldn't it have?

Looking it up on wikipedia, most suicide bomber vests weigh roughly as much (5 kg) or up to 4 times as much (20 kg) as all the sarin used in this attack (5.45 kg). I've never heard of a single suicide bomber, using a vest, injuring 1,000 people. So I am inclined to think the chemical approach is more efficacious.

In fact that's another little nitpick I have with the article - it's high explosives that heavily benefit from tightly packed situations, as they're a one-and-done sort of deal. The sarin gas though was able to be spread all along a tube system, and cause problems for huge amounts of people.