The free .tk domains are only free for 1 year. And even if you are only going to use it for a year, some people would rather not give out their credit card number for a free trial.
Please stop spreading misinformation. You don't need a card, you don't have to provide any identification at all. The domains are free for as long as you want (I've been using one for the last 3 years), you just have to click a button once a year, and freenom sends you emails two weeks in advance.
Perhaps I’m mistaken, but I believe at one point in time, years ago, they required a card for the free registration. It certainly wasn’t my intent to spread misinformation.
I have recently tried to pick up a domain name on Freenom and had extreme difficulty getting the website to respond and issue me a domain name. Once I finally locked one down that I liked, my account was dissapeared without a courtesy email or anything. To be fair I was using obviously anonymous/pseudonym details, but I would have still expected a courtesy email.
No, they can be renewed for another free year indefinitely, as far as I know. I don't believe they require a credit card number, either. I've had a few freenom domains I've renewed for several years in a row and just got some new ones a few months ago; it's a very useful service.
The free .tk domains are only free for 1 year. And even if you are only going to use it for a year, some people would rather not give out their credit card number for a free trial.