There are many travel credit cards out there that offer different kinds of rewards, from general points programs to branded hotel and airline cards. I think they are great if you use them right (and pay off your balance at the end of each month). They are better than cash, especially when you can get so many rewards and freebies from them.
No matter how long your trip is, you should have a special credit card for when you travel. Travel credit cards offer too many benefits to pass up. With bonuses, I've accumulated probably over a million points. Here are just some of the goodies I've earned:
More than 400,000 American Airlines miles
More than 120,000 United Airlines miles
More than 100,000 British Airways miles
More than 50,000 Virgin Atlantic miles
Four free nights at the Marriott
Citibank points for two free flights to Europe and $300 USD cash
Hilton Honors Gold membership and 60,000 Hilton Honors points
A free first-class ticket from London to Hong Kong
Dozens of free hotel rooms at the W Hotel
That's just for starters. I've been travel hacking for so long that the list of things I've earned could fill a whole book.