I don't really see the point of sharpening it lol.
Those so called "full tang battle ready" isn't really dependable as well, especially those made in China. (Of course I'm not talking about Paul Chen/Han Wei, they are China made but they are usable)
Unless it's branded, otherwise, don't even try to swing them around as you won't be happy when you see the whole blade with tang flew out of the handle, hopefully no one is around.

Of course..I myself have thought of ordering an Iaito(Practice blunt katana for Iaido training) from a company named "Jidai" in Japan, they are very expensive, one basic Iaito cost up to Rm 2k+.
Well..I was an Iaido student...But I was using Shinken instead of Blunt iaito..I fear for myself that I could made some serious mistake..So I tried ordering but just so you know, even the Iaito won't made it into Malaysia..A total let down.

I guess the only way I can practice Iaido is when I'm out of this ridiculous country.

Talking about a real Katana? Heh..You could say it's a dream of mine..
A Shinsakuto(Newly made Katana) with only bare blade cost around 10k - 60k(In fact more than this) depending on the blacksmith..Let's not forget about those mounting lol