These software programs are quite basic and easy to learn. Spend a few hours playing around with the simple programs and you’ll be turning out designs that are as good as any examples made on their official web pages. If that’s what you want to do, fine. But if you push those software to its limits the results will still be very unsatisfactory.
While learning a software like Autodesk Inventor Fusion is an investment of time, the learning curve is steep and it will take long hours for many months to become comfortable with it and before you can turn out professional level work, even more time will be required, but that’s the difference. You can definitly produce high quality designs and you may have the chanche to work for important companies. You will master a skill that others hold in high regard as well. The payback in new valuable skills will be immensely greater.
Tinkercad is useful for simple projects and not everyone needs to be a CAD pro. The simpler programs must be almost immediately useful returning value for the time spent or the scales quickly begin to tilt away from simplicity and towards real capabilities.