It would be nice if we were given the option to sell, store, or hatch eggs directly after breeding(before sending it to the hatchery) That way you don’t have to wait hours for an egg to hatch so you can sell it because it wasn’t what you wanted.

Do you think you're getting genies darknubis and pandalf by accident? It's intended to give you a lot of useless stuff so you spend gems speeding up, that change isn't happening

As @tintum said its a way for you to make you spent gems. So when you do a breeding event make sure you set yourself a budget like dont spent more then x gems (like 245, cost of a legendary) also keep in mind that percentages are low not more then 5% if you arent using the jokers not more then 10% if you do.
To see the result you have without spending the gems: open game game turn wifi and mobile data of speed up hatching look at the result log out of game and progress will not be saved. Good luck
Ps wath you suggested is been asked for many times befor also including a hatching guardian