What are Some of the Arguments Against Iris/ Fingerprint/facial Recognition Systems?

These are very well established biometrics options. They offer good results, but they need specific readers/ scanners at all access points. Most of the access equipment wears out in a few months, to reduce the effectiveness score. Dust, moisture, wear-tear, low maintenance affects the results of a scan. Voice biometrics will work through any mobile/landline and does not need any specific equipment.

It is highly aware of “liveness” [actual human participating in the authentication], less intrusive, inexpensive and scores very high on EER [equal error rate]. Go for it.