I haven't had a chance to work with it yet, but I had the same idea as you.
It's easy to store up a selection of components, and there are tons of free project plans all over the net.

Yes I have used them, have a couple kicking around. While you can use them as you say, there best use is for proto typing the circuit you are building as in if your circuit has a oscillator in it and if you cant do the math to figure out component values you can quickly plug in different cap or resistor values to walk yourself to the target frequence, just saves time in designing, I would design on the breadboard but once I had the circuit functioning the way I wanted then I would remove the components and hard solder them on a separate board, maybe through hole and point to point wiring if your not up to etching your own board. On a bread board component leads are held by friction and that just wont do on something that needs to operate reliably over time. if your learning about circuits its a great way to get started building different project, its fast, and no soldering needed.

I forgot about veroboard, after you have your design worked out on your breadboard, you can solder the components straight onto veroboard for permanent circuits. the two go hand in hand