The peach trees in this
thread from seed are very impressive-looking compared to all the pathetic, grafted, massively overpruned trees I've seen being sold in nurseries. It's really sad what nurseries do to peach trees when they can look like they for example do in the OP, which is how they grow the best and most productively. It is very frustrating to see all the grafted trees sold in nurseries already having dozens of scars along the stem from (over)pruned branches.
As other people have said if way more people grew peaches and nectarines from seed we would have had way more different varieties adapted better to both colder and warmer climates and different humidity levels and better
local pest resistances. The
Native Americans were notorious for having so many different, unique peach and nectarine varieties because they were all propagated and spread by seed and they loved growing peaches in their orchards. There's no good reason to NOT grow some peaches and nectarines by seed if you have the space and not too bad of a climate for it!