This item is all about convenience. You could easily make this from parts available at your local hardware store, but you'd have to buy more tubing than you need and may not have any use for, cut it yourself, etc. So, if you are already buying other things from here, why not?
As far as function, it works well for what it's intended for.
The issue I had is that it came with the compression fitting tightened so far that I nearly had to put one end in a vice so that I could use two hands on the nut to loosen it. Considering the application, there's no reason to ever tighten the compression coupling more than 1/4 turn past hand tightened even when in use.
This is a problem because not only is that gross overtightening not necessary, you have to take it apart to install it anyway. I spent more time trying to get it apart than I did installing it once I was finally able to do so.
In addition, because it was overtightened so much, the sleeve portion of the compression coupling was deformed and crushed into the tubing below, deforming the tubing in that spot.
Next time I might just opt to going to the hardware store and building something similar myself.