I would not leave anything of major value in your bag in the CA, for example leaving an iPad in your bag would be a very bad idea. One does have to walk past the attendants at the front desk to get into the luggage area, and there is a camera mounted in the storage area, but still the agents can be distracted and of course also don't know if someone is removing their bag or someone else's bag.
So if you make sure your bag is not easily confused with others and you have nothing of major value, then I'd be fine with leaving my bag in the CA. You could even mention to the agent when you check in that it will be there for quite some time, just in case they check on things.
I would not use the paid service outside by Gate A. I've heard horrible stories about them and they are very expensive!