Take, for example, my vacuum cleaner. I got rid of it because it was an outdated model, and instead diligently wiped the floor with paper towels and rags. But in the end it simply took too much time, and I had to buy a new vacuum.
And then there was my screwdriver. After throwing it away, I tried using a ruler to tighten a loose screw, but it snapped down the middle. This almost reduced me to tears as it was one I really liked.
All these incidents stemmed from youthful inexperience and thoughtlessness. They demonstrated that I had not yet honed my ability to discern what brings me joy. Deceived by their plainness, I failed to realize that I actually liked them. I had assumed that if something brought me joy, I would feel a thrill of excitement that made my heart beat faster. Now I see things differently.
Feelings of fascination, excitement, or attraction are not the only indications of joy. A simple design that puts you at ease, a high degree of functionality that makes life simpler, a sense of rightness, or the recognition that a possession is useful in our daily lives—these, too, indicate joy.
The real gray area is when you have some poor quality tools which you do need and use, and you can't yet afford to replace them with ones that do spark joy.
Personally I try and buy tools second hand, as they are typically cheaper and of better quality than the new tools sold in hardware stores. And they can be resold for about the same I paid for them, making them free to own.
Apart, that is, from their alleged intrusion on my personal joy from cluttering my workshop. Which is rubbish - workshops should be exempt from this joyful thinking, they are places where you want to find that useful piece of scrap material lying somewhere - anywhere - when you need it.
What I think she would say about a workshop is that a well-organized (tidy) space, where everything has its place, so you know where to go when you need something, and where it goes when you have finished using it, is going to make you a happier person than having to dig through a toolbox/drawer/scrap pile to find the right tool or piece of wood.
In my experience, workshops are not devoid of joy, unless you work only on things you don't enjoy or find pride in, which seems unfortunate. My workshop memories are of my granddad making wood products of all sorts, my dad working on the car and various household projects, and my brother creating toys of various types (e.g. making our own cornhole set). The frustrations in the workshop were typically of not being able to find something I knew was there, but perhaps that isn't what you are after or expressing here.
One of her rules seems to be "Try to organize your objects in a way that each one can be viewed without having to move another". Pile is worse than a Box is worse than trays/drawers. Organizing your scraps by category and size would likely make them provide more utility to you?
But as someone with a cluttered workshop trying to figure out a good organization scheme, I may be thinking too much about this. Anyone have a quote from her about workshop/scrap materials?
I would have said "utility" if I were writing it, but if "joy" reaches a greater number of readers, then it's probably the better choice. And you knew what she meant, anyway.
Speaking for myself: I have more objects that have utility than I have space to put things away, so there's got to be more to it than that if I want to avoid clutter.