Per Stormin Mormon:
Does braking with the left foot increase the
risk of accidents?

From what little I have read, there is disagreement on the answer.

The traditional answer is that left-foot braking is, somehow, less safe.

I can't remember the term-of-art for it, but there is a recognized cause
of accidents that consists of the driver stepping on the accelerator
when they were trying to step on the brake.

A few months ago there was an article in the New Yorker about vehicle
defect investigation and vehicle recalls from an engineering perspective
in which it was mentioned that some people think that left-foot braking
may actually be safer because it reduces the chances of a "wrong pedal"
error to nearly zero.
--
Pete Cresswell