Actually, it does make sense. Let me type this slow so that everyone can understand.
You have a servo in the wing. The wires coming off of it are too short to reach the root of the wing. So you go and buy yourself (let's say) a 12 inch extension. You connect that extension to the servo lead, and secure it using heat shrink. Now, the extension is long enough to protrude out of the root of the wing, and into the fuse of the plane when it is put together.
Now, you have a receiver, right? So you take the aileron channel, and you plug in a Y connector. Now all you have to do is plug the wing in, screw the wing to the fuse, and make sure the servo extension goes through it's little hole, and into the fuse. Now, connect the end of the servo extension to the Y connector and you are done.
Do you need a clip between the extension and the Y? No, you do not. The only reason to secure a connection together is becuase it is hidden (like in the wing) so that you can't examine it easily when you are setting the plane up. The connectors that are in plane sight can (and should) be easily secured for the day's flight.
Now, if you do not want to mess with a Y connector (becuase you may want independent subtrim adjustment, or differential programmed in) then that is a simple fix as well. You now run not a Y out of the aileron channel from the rx, but instead you run a 6 inch lead from the aileron channel, and a 6 inch lead from the slave channel. You put a different color tape near the end of each wire so that you know which one controls which side. You then put the same color of tape on the corresponding servo extension end, and it becomes a matter of matching red to red and blue to blue. I've done it both ways, many of times.
The only reason to fret about servo connections is if they are hidden, as flight after flight after flight of vibrations can cause them to loosen up. However, one also has to worry about corrosion after a while, that is why I have done away with extensions all together (that and their cost). Instead, I opt to cut the servo lead, and splice in the appropriate amount of servo wire.
I'm sorry if that is confusing, it's the simplest way I know to explain it. Not everyone's opinion has to be the same.
I personally see it as rediculous to pay close to 10 bucks (with shipping) for 3 of those clips.
That's just my opinion. If the OP wants to use my method then he's welcome to it. If he doesn't understand it still, then he's welcome to ask again.
Anything else is taking away from this post.