I’ve never quite understood the appeal of giving general-purpose gift cards as presents. After all, they’re no more thoughtful than cash; and they’re less convenient than prying open the wallet and peeling off a few bucks.

However, until a few hours ago, I never fully appreciated what a terrible value these spend-anywhere cards are. I’m hardly alone, according to the results of a survey released today by the Consumer Federation of America and the National Association of Consumer Agency Administrators.

General-purpose cards are issued by banks or credit-card companies, and they’re accepted at the same retailers that accept the affiliated credit card. These are different from store cards, which are honored only by the retailer issuing them.

Americans buy more than $50 billion in gift cards every year; and general-purpose gift cards account for about $4 billion of that business. According to the consumer groups’ survey of 1,004 adults, more than a third of consumers say they’ve given or received spend-anywhere cards in the last two years.

That’s problematic, because of the survey’s other findings. The survey, which has a margin of error of 3 percentage points, revealed that:

• 17 percent of those who said they had received a general-purpose card said that they had had “trouble spending the entire balance because a store refused a split payment on a purchase greater than your card’s balance.”
• Merely a third of respondents understood these cards cost more than they’re worth. (Typically, consumers must pay between $4 and $7 on top of the card value.)
• Only 54 percent knew that, 6 to 12 months after purchase, a monthly fee can is often charged against the balance on a spend-anywhere card. (Recently, American Express dropped monthly charges on its general-purpose gift cards.)

Stephen Brobeck, the CFA’s executive director, told reporters today in a telephone press conference that there are four common complaints that can make spend-anywhere cards less attractive than cash: Consumers often don’t spend the entire balance; monthly fees can decrease the card value; the cards themselves can expire; and some retailers — even individual clerks at some stores — refuse to split the cost of an item between gift card and another form of payment.

The problem is most American don’t know about these drawbacks until they receive the spend-anywhere cards and try to use them.

“Consumers clearly like the convenience and flexibility of general-purpose gift cards but also are largely unaware of their costs and risks,” Brobeck said.

The good news is that, starting August 2010, companies will be prohibited from charging fees on gift cards if they’ve been used in the previous 12 months. That regulation is part of a sweeping credit-card reform legislation approved by Congress this year.

If you’re still undecided on general-purpose gift cards, check out a brochure for consumers developed by the two watchdog groups. American Express will distribute 1.5 million copies to major retailers that sell the cards, including Walgreens and CVS.

The brochure recommends that consumers pay close attention to the card’s expiration date and charges, and then spend the balance quickly to avoid losing value through fees or forgetting about the card.