If you have never designed physical objects before it is really challenging at first. The learning curve is pretty steep and, at least in my case, I discovered that I didn't have a mental language for thinking about functional 3D and mechanical design. You also start to look more closely at the objects around you and think about what went into designing them.
I started doing 3D design about a decade ago, when I got my first 3D printer. At first using free modeling in CAD and then later learning how to do constraint based and parametric designs in Fusion 360. This felt slow and perhaps limiting at first, but when you get used to it, it will save you a lot of time later and allow you to make more useful designs that are much easier to evolve and vary.
I think it took something like 4-5 years before I printed something someone else had designed. Mostly because I used 3D printing to make custom parts for my own projects, but also in an effort to force myself to learn. I know the learning curve was steep, but for some reason I have forgotten how much work it was to learn.
Now there are so many useful designs, designed by people who are a lot better than me available everywhere that I do print a lot of things others have designed. But I think learning to design things yourself is a really good opportunity to learn useful skills.
For instance, I had never anticipated that I, a software engineer, would get paid, by an actual customer, to design parts for their projects. Or even consult on physical design for someone doing product development. I am by no means at the level where I'd put it front and center on a resume, but I can design, and to some degree, manufacture simple mechanical parts.
(Along with 3D printing I've been doing some CNC at a very hobbyist level. I would still say I am very much a beginner when it comes to machining metals, but it is really fun to see that you can make reasonably precise metal parts for real applications (car parts) at home in my garage with not that much effort. This weekend I'll be doing thread milling in aluminum for the first time on a part that requires M3 screws)