Actually, even if they give an explicit answer, it does not guarantee anything. Since it is free, they can later say that due to some reason or other, they have to terminate this arrangement when the domain name expires but you can keep that name for a small fee. Having said that, I suppose that since they have stated that it'll remain free, there is a chance that it will be free in the near future (until such time they find that it's more lucrative to get people to pay).
(But I personally still prefer to register .com, .org, .net domains for serious sites. But then of course, I'm not situated in K... [ whatever that country is - forgot how to spell it ].)