Looks like maybe Sarvice, or Serviceberry (Amelanchier)
Crab apples are great. They are very high in natural pectin, so you can use them in your jams. I grate them up into the jam that I am cooking. I also grate them to dehydrate and when I make oatmeal, instead of using the grannysmith apples that I used to buy, I just throw in some of the grated or chunked dried crab apples. I probably still have 3 gallons of dried crab apples from last fall. I like them tart. We also use the chunks in our trail mix. I think they actually taste better dried.
When I made a batch of apple pear wine last fall, I used some crab apples in the batch and it made it taste more like a hard cider, which turned out great and I will have to do again.