Less pain for patients as diameter of injections is 0.15mm.
Injection spreads into cone shape so there is no fluid reservoir.
No needle to cause trauma or cross-contamination problems. One gun can give many different injections by simply changing the Injection Head. Dosage is changed by moving the dosing blades. Single dose at multi-dose prices. Even allowing for priming the Injection Head and the small volume left in the vial, there are big cost savings as there is no wastage on each dose given.