Teenage Modeler
Sorry if I made you angry, this was meant to be a curious question, not a rant.
Curiousity is a good trait to display. It should be rewarded, so just know that I'm not ranting, either.
Some of us have gadgets to open stuck paint jars because we've been building since we were kids and we've grown into old men. Arthritis, nerve damage, neurological issues, and the general wear-and-tear of time makes these "unnecessary" tools a blessing to those who need them. If you've ever had a square bottle of Testors explode in your hand when the vice-grip pliers came into play or if you've ever nearly severed a finger using a dull hobby knife to pry off a crusty Pactra cap, those gadgets could have potentially saved you from learning those hard lessons about how to properly store your paint so stuck lids aren't a concern to begin with.
Why do I have purposed scribers and gravers? So I don't have to use the back of my hobby knife. When I do that, I wind up with lines just as wide as the tip of the knife, which is often far out of scale; the lines tend to be a bit on the rough side because the tip likes to skip as it catches and grabs at the plastic; the knife has a hard time rendering circles and ovals; and I sometimes have to deal with the tip breaking off the blade and embedding itself in the plastic. With my scriber, I cut smooth, clean curls of plastic, which leaves little or no clean-up;: I have finer control over the width and depth of the lines; and it can handle shapes such as ovals and circles with far greater ease than the knife. It's simply the better tool for fine details.
Why do I have a lot of different brushes in different sizes? I have a lot of reasons for having an assortment of brushes. For instance, I have a set reserved specifically for metallic paints. There is another set reserved for working with pigments and weathering powders and others reserved for use with glues or solvents. There's a big mix of sizes, because every size fits a specific job or function. Beats the hell out of using the square bristle nylon brushes I used as a kid for every job at the bench.
Why all the paint? Depends on the effect I want. For instance, I prefer enamels for metallic effects, where I prefer to use acrylics for cloth and skin tones. I use artists oils for washes and weathering applications. Because I literally use only a few drops of paint at a time, there are quite a few bottles of different paint sitting on my shelf, but that's a bit of a blessing in its own way. The closest hobby shop is 250 miles down the road, so there are no quick trips to get more.
As you progress in the hobby, you'll find the tools that make your time at the bench a little easier and perhaps even a little more rewarding. In the end, whatever tools make their way onto your bench will serve your purposes in a way that only you can every really appreciate. They will fit your abilities, techniques, and preferences, as well as the job you have at hand.