Another downside is that I will owe my wife $20. She claims that she can read animal behavior very well, and before I even inspected the hive she bet me $20 that the bees were planning on swarming. I agreed to take the bet. She told me that she can read animal behavior so well, she could see that our cat wanted in on the action for $1. So now it looks I am out $21. Rats.
The benefit of letting your bees raise their own queen is that it causes a break in the brood cycle, which does not hurt the bees so much but it does hurt the varroa mites which reproduce in capped cells.