You can always extend a wire snare with braided cord. In fact I use a lot of snares that are made entirely from braided cord.
Wire is handy for snares because it holds an open shape...whereas cord needs to be supported more for the noose to stay open.
All you really need is enough wire to make the noose and form the 'eyes', plus an inch or two extra for supporting the noose. The tethering can be done with other materials.
A squirrel snare might have a noose diameter of, say, three and a half inches. So by the time you allow the extras, you might find that fourteen inches is a practical length to make squirrel snares if you tether them with cord. Mind you, I've never tried to snare a squirrel so I'm not speaking from experience, but I'm sure you get the general idea. We don't even have squirrels in our country.
If you are going for a bigger animal you will need longer wire.
Wire can become kinked and damaged after catching something, so you might only be able to use it once. Cord snares might be able to be used many times if the animals don't chew it. If you use it to make a spring-up snare, it is unlikely that the animal caught will think about chewing the cord. I've caught many animals with plain cord snares and only an insignificant number have chewed through the cord. I don't generally use snare locks with cord, so the snare is free to fall off the animal if the cord breaks away.
Generally you have to set lots of snares if you are serious about catching something. Of course it is possible to catch something with having just one snare set, especially if it is baited...or if you have set it on a trail or den entrance that has frequent traffic. I have set a lot of snares and if I get three animals out of ten snares I have done well.
Sometimes it might be a good idea to use some thin copper wire wrapped around some light braided nylon cord to form a snare. A secure snare eye can be securely tied in the end of the cord, and the wire will provide stiffness, thus enabling the noose to stay open. Here is a picture of a rabbit caught in a cord snare that was reinforced with a bit of very thin copper wire. The wire I used was the enamel coated stuff that motors and transformers etc are wound with.... there is a ton of it around: