The cannula-versus-needle question is almost always discussed as a matter of clinical preference — and at the level of which instrument to use for a given patient and product, it is, and it belongs to trained injectors. But for an owner, the choice also touches three things that are squarely your concern: the per-unit cost of the consumable, the time a treatment takes, and where your liability exposure sits. The useful insight is that these don't always pull against each other. For certain applications, the technique that's clinically safer can also be the one that aligns with lower complication-related cost — a place where patient safety and business interest happen to point the same direction.
This is general education for owners, not medical advice. Clinical technique decisions belong to trained injectors and your medical director.