According to an alarming ad I saw the other day, trading stocks is strictly for grandmothers. It's boring, the ad asserts. Safe. Yawn-inducing. But currency trading, the ad insists, is "on the other end of the thrill-o-meter from a rocking chair" -- the always-on, open-around-the-clock place for real investing daredevils to be.

I've got so many objections to that sentiment, I hardly know where to start.

For one thing, since when do grandmothers need to find themselves at the top of the thrill-o-meter? Do any of us even need that? Jumping out of an airplane might be a big thrill, but given the risks, it's not for everyone. Same goes for auto racing, climbing Mount Everest, or any number of other daring feats. Sure, a successful investment can be a bit of a thrill, but investing isn't about maximizing excitement -- it's about building a secure future.

Besides, getting into the stock market solely for the sake of trading is counterproductive. The best investors have generally earned the biggest returns over long periods of time, not by trading in and out of the next big thing, but by buying and holding stock in solid, growing companies. That may not sound pulse-pounding, but it's tough to argue with the results.

Besides, when would we need 24-hour access to trading? The ad suggests that the six and a half hours each weekday that the stock market is open just aren't enough. Why not? Few of us trade more than once a day; like many investors, I rarely trade more than once a month. Berkshire Hathaway's immensely successful Warren Buffett has said that it would be fine with him if the stock market were only open one day a year.

The ad paints a rosy picture of a risky venture, suggesting that investors can expect big thrills and big profits all at once, and that doing so is easy enough for your grandma to strike it rich. Is it any wonder I'm worried?

What others say
I'm sure that some people are making money in this arena, but this particular ad seems to me like the day-trading craze all over again -- another get-rich-quick lure poised to wipe out people's fortunes. Currency trading can cost you much more than you initially invested. Here are some words of warning I found at Yahoo! Answers:

I've read 5 or 6 books on [this currency trading] trading. I've spent countless hours studying various technical analysis techniques, and I spent months trading in a demo account before trading with live money. I still lost most of my account value. [This] trading is very tough and the cards are stacked against you.

The bottom line
Am I slamming this arena completely? Not at all. But I hope no one rushes into it on account of ads like this one.

If you or your grandmother would like to make a lot of money over the long term (and remember, many grandmothers have decades of life still ahead of them), I'd recommend sticking with top-notch companies and mutual funds. The T. Rowe Price Media & Telecom Fund (FUND:PRMTX), for example, has racked up average annual gains of more than 17% over the past decade.

To discover more exceptional mutual funds, take a free, no-strings-attached trial of our Motley Fool Champion Funds newsletter. Even your grandma knows that's a good deal.

Longtime Fool contributor Selena Maranjian owns shares of Berkshire Hathaway, an Inside Value pick. The Fool's disclosure policy is always nice to its grandma.