I've got a ton of choke-cherry trees around, and they too get tons of flowers. Tall trees, they produce little berries, not the good edible kind. The flowers and berries are in more of a spray of blooms versus a cluster on my pie cherries. They bloom around the end of may, I think.
I haven't actually seen bees on them, but I'm sure that they are. That time of year there is so many things blooming that they don't focus on the cherries, like they are on the maples right now....yesterday (and I'm sure today) my maples were buzzing loudly enough that my wife and kids thought that there was a swarm out there.