"A bit hard when you are a kid!"
Hard to tell that from your much more mature sounding initial post 
It can be a hassle rounding up all the parts to make something like this from scratch. These kits make it easy to have a little fun and to have something completed that can be put aside. Many home projects get bogged down when the design has been debugged, the protoboard is full of parts, and now its time to put it all into an enclosure and getting batteries installed, etc.
I came across these recently at Staples
"really useful boxes" and have mounted some stuff. Easy to work with plastic, variety of sizes (and color, depending on the size), not very much money, and can be picked up locally if you have a Staples or maybe nearby. Lot easier to envision your design going into something when you can hold the box in your hand.