I wouldn't say they're useless, maybe if you're trading 1 lots sure, put on a decent sized position and ignore vega and see what happens...anyway I'm not sure what model they are using, most likely just regular black scholes, I would have to say it's probably implied off of that model. Historic vol being calculated based on some amount of time (maybe 30 day)? I mean are you going to buy 300 vol in some pharmaceutical the day before it releases news? Most likely not, sure it could go to 500 vol but that just starts to get dicey...
Also you could always trade just vol and hedge your deltas so that you have no directional risk (underlying wise).