Your process for making a rattle sounds perfect: using what you have in just a few minutes to make something you can use. There are lots of connections there, connecting you with your environment (resources), needs, abilities, and time available. A project with a beginning, middle, and end that goes out into the world with a purpose. How very satisfying! While your baby may not even notice the rattle, he may spend a small corner of his mind wondering forever what the 'hidden meaning' was behind the choice of colors and patterns in that rattle.
I vaguely recall wondering very seriously what the plot was in a little book I had as a small child: "ABC with Ant and Bee." Every page seemed disconnected from the one before -- the plot was very esoteric.
The title "Making Do" implies all kinds of negative stuff -- but maybe that is just me.
FAO Schwartz (among others) seems to be capitalizing on the ugly critter phase (probably started by that delightful book of "Stupid Sock Creatures" by John Murphy). Going from there to the Museum of Natural History in New York reminded me more that crocheting critters (or knitting them or sewing or whatever) may be a meditation on really cool shapes: some kind of shape for a body (maybe), adding fins, flippers, tails, ears, mouth (with or without teeth/tongue), nose, and legs/arms that keep dividing into smaller bits like toes/fingers. How delicious.... And then applying those ideas to the natural shapes suggested by specific stitches makes it more fun.
And it makes you look clever, too.