When I grew up, we had several crabapple trees in the yard. They very frequently bore fruit. My mom always told me these were toxic to eat, so I stayed away from them. Honeysuckle and blackberries, on the other hand...
I just googled it. It's a common myth, I suppose?
https://www.alamy.com/home-made-crab-apple-jelly-malus-evere...
https://www.allrecipes.com/recipe/40275/mary-wynnes-crabappl...
https://thequietfoodie.com/my-first-ever-crab-apple-jelly-re...
As raw fruit they are perfectly edible when mature. The flavor is a mild apple flavor, a little bland an can be sour also. As in all apples, the seeds have cyanide, but as long as you don't eat them or filter the seeds after cooking it, it will not be a problem. Just don't eat it whole.
The immature fruits are hard as a steel ball, so there is a risk of suffocation with children, but apart if this, if you discard the seeds they are perfectly edible. I ate them many times, even if I prefer to let most in the tree for the birds.
"Wild" apples are Malus sylvestris or just feral domestic apples Malus domestica.
Crabapples comprise the rest (>30 different species) of apples and its hybrids. Malus florida from Japan is famous for its glorious blossom for example. Malus sieboldi from China or Malus bacatta from Siberia are also crabapples. Some are true to seed, but other aren't and there are many cultivars selected by blossom or fruit display.
There are some crabapples cultured specifically for culinary purposes, like Golden Hornet that bear heavy amounts of small yellow fruits. Very good for compote and jelly.
And a lot of cider apples