A good driver from a test driver?

Hamilton started his fantastic racing career being a test driver. Do you think it is a good way to start your career in the same field? Will you get better luck if you use this way than if you do the "normal" way?
I think it's definitely a less conventional way to go about it, as you aren't bound to get noticed by anyone while test driving cars. If you're willing to do the work on the side to put yourself out there, though, it definitely can't hurt for your resume!
It works for F1 I think. I've seen drivers coming up through the ranks there, beginning by being test drivers. Even in NASCAR, doing things for teams is a way to get noticed.
If there's a will there's way, whatever way it would be. There is nothing wrong becoming a race car driver from being a test driver. I think they even have an edge to those drivers who have made their through conventional racing because test drivers feel how the cars are doing. They can use that advantage while racing by knowing the capacities of the car they're driving.
I believe that the talent scouts are always aware of every potential drivers they find. Being a test driver is a great way to get noticed. That's why I think it can be a good option for building career as a driver in this field.