Whilst it is used all the time for Australian warrants and eto's it can also be applied to listed company options. There is a formula for calculation annualised volatility also however if the price has had significant up and down movements 100% is pretty close to the mark.
I have been using BS for the past 20 odd years (I previously traded warrants and eto's full time) and whilst the market doesn't always agree with it, it provides a good estimation of fair price and time decay.
VOR Price at posting:
1.9¢ Sentiment: Buy Disclosure: Held