Hatchery birds are indeed a good way to learn about raising poultry.
However getting them and working towards perfection with them may not be at all possible, especially in the industrial or hybredized varieties.
If working towards a standard of perfection, why not start with more perfect stock, and then working it further?
It is tremendously endless work to perfect a breed..and takes years.
In the end, you will always have to buy more perfect stock to breed into the imperfect stock you have already purchased and invested great amounts of time and money and love into.
Then to have to cull as they are imperfect, instead of being able to breed them, is not money wise or worth while.
Breeding an imperfect bird to an imperfect bird will just get you an imperfect bird, and that that just took about 2 years right there.
The fast remains, if you want some chickens for fun, and eggs..then get hatchery birds.
They have been engineered for years for this very purpose.
But if you sincerely want to work with a breed you find attractive and intriging, and you want to raise them, perfect them, and even show them, then I strongly advise you start with the good stuff.
You cannot make a silk purse from a sow's ear..and you will be sorely disapointed in trying to make SOP birds from hatchery birds, RIR for a good example, or Ameraucanas for another example.