I suppose that's the attack scenario those systems (at least in phones) are supposed to protect against, to be fair. Suppose the alternative might be that some users use a predictable pin or none at all. Fingerprints or the iris sensor is an improvement for them because they are quick and easy to use.
Of course it's still good to deflate the hype around Iris scanners a bit and demonstrate that it is currently a very limited technology after all. Especially considering their remark that iris scanners spread to other devices too.