Actually, it is no big deal to fasten a cable release when needed, but it can be a pain in the neck occasionally...
But then, you will have to remove it when you're done and mount it again and again.
Sometimes your fingers are too cold or slippery...
Well, I reckon you've got the picture.

Linhof is the only one afaik, who came with a solution years back. It is called "RapidKlemmung" or QuickSocket in English.
The early ones were black and a had white part.

On this image you can see how it looks like.
It is an extremely nifty gadget, what makes mounting a cable release a jiffy.
Just push it in till you hear a click and off you go...
When done just slide the red dot down and pull your release out!

But not any cable release, just the special Linhof cable releases that is. How come? The Rapidklemmung on the lensboard doesn't accept a standard screw-in cable release. Instead it's designed for a “quick release” cable, but fortunately, the shown "Cable Tip Adaptor" converts a conventional cable release to this interface.

If you look closely, you will notice the difference. The Linhof cable release has a deeper ring at the end of the thread. The little spring clip in the Quicksocket will catch in here.

The trick is to screw this little cone "Cable Tip Adapter" on your favorite cable release and it will snap in. It is a Linhof part also and might not easy to find however. There is another solution though, work with a Dremel on your release till the little clip snaps in.

Here you can see it very clearly..If you can manage to use a dremel and get a deeper ring just after the thread, it will work as fine!

The Linhof Super Technika V dressed-up with the whole caboodle.
As said before many items from Linhof can make working with a Speed Graphic a little more comfortable.
If you find one of those thingamajigs, give it a try it on your Graflex lensboard...
The cable release works much smoother than the exposure button on the housing of the graflex, which requires considerable pressure.
When using long exposure times (from 1/15 sec and up) it is preferable to use the cable release instead.

Real Size, compared with a ballpoint: