Yes, we love growing apple trees from seed. Each tree is genetically unique. All apple varieties ever discovered have come from a single seed. I have heard that one in a thousand seedlings will make a good apple. I believe this is not true. Around here 1 in 3 or 4 wild apple trees makes tasty fruit.
Seedling trees have the advantage of being on their own roots. They can have very long lifespans, sometimes over 100 years.
Malus Siervesii is the species of seedlings we have available right now. This is the species from the Tien Shen Mountains of Kazahkstan from which virtually all domestic apples have originated from. They contain an enormous, untapped gene pool from which plant breeders are experimenting with to find new disease resistant varieties.
Trees are 10-18" 1st year seedlings