In past store event I would agree with you but now they are starting to give you options on what to do with these chest on the last event and this one.
Last event you level them up by chance and trade them in for a prize of a guarenteed nature (still random but lets more focus on better outcome random) or sell it to someone wanting to take that chance, or open it yourself.
This store event is very similar, you can upgrade to eliminate many of the low end things, take a chance with low end items in or trade to a more focus less random prize. So yes it still random but you can par down the random if your not looking to hit the lotto. Its not ideal but less risk more reward but more expensive. So short of straight out buying items I think this better than a completely random event. Don't let the high end people fool you they are making a fortune off this event, I know people that made a couple 100's billions off this already.