If you are riding flat trails and relatively low speeds, this may be ok. Bike brakes are pretty marginal as is, it is easy to lock a wheel up and skid, and a
skidding front wheel means you have only a few seconds to regain control and prevent a crash. Since the wheel is smaller, and you are tilted backward a bit
you are less likely to take a header, but I suspect you could still manage to do a header in an emergent situation. One brake means that you can scrub speed off much more slowly, so going above 15-20mph and needing a sudden stop will give you sense of the meaning of Einsteins' concept of time dilation,
if you avoid a header. Steve