It's more that you don't NEED a one piece cable, I'm not sure why you want to spend money on an extra adapter??? That's $70 of consumables, material, argon you could be buying...
Some machines have the gas line incorporated into the dinse connector and you HAVE to buy a one piece cable, the CST 280 doesn't have that.
Are you planning on upgrading to a machine that does have an internal gas valve (in the dinse connector or otherwise)? If so then go with a one piece cable and look at it as an investment for the future.
Yes, in the future I do plan on getting something specifically for tig with the gas through dinse connection like for AC tig, so then I will probably move the tig torch to it.
They both weigh about the same, one is a gas hose with electrical cable around it, the other is a separate gas hose and separate cable... they both have to do the same job so the cables and hoses are the same size and weight just combined in one version.
You can buy a cable sleeve for either version and it's not a bad investment, it all depends if you're using this torch in a field application (mud, rocks, heavy foot traffic, etc.) or in your garage where you are the only one around and only one going to use it. If it's the latter than a wrap of electrical tape every foot will work fine.
So reviewing all that has been mentioned I think I will be looking for a 1-piece cable 26 and then put a gas lense on it to help extend the tunsten out for getting into smaller spaces.