Why checks and balances made in the first place?

That's a good question given that all three branches have managed to expand the scope of their jurisdiction without any regard for the Constitution that endeavored to keep these three branches balanced and checked. Since all three have gained their newfound and mysterious powers simultaneously I suppose it could be argued there is still a balance the problem is they got rid of all the checks. It's not Chess we are playing any more, it's checkers. King me!

Why checks and balances? Because the very nature of government is to grab power, to rule over subjects and to tax, tax, and tax and then tax some more and when that's been accomplished they'll tax again to pay for all the government employees who worked so hard at collecting the taxes. Under the Constitution of the United States it is the people who have granted a limited amount of power to elected officials and appointed officials for a limited amount of time. Given the power hungry nature of governments it was decided a separation of power into three branches, each equal in power to the other would jealously guard their own power and prevent the other two branches from consolidating their power. Obviously, it never occurred to anyone that the three branches would collude with each other in order to expand the scope of their jurisdiction.

Whether the framers of the Constitution considered this possibility or not, they certainly considered the possibility of tyranny arising out of democracy and wisely enumerated certain rights within the Bill of Rights. There is actually a fourth branch or more technically a zeroth branch which is the people, and no matter what sort of political shenanigans and legal circus our government may try to thrust upon us, our natural rights our ours and no one, not anyone, can ignore that. Just because an administrative agency claims to have jurisdiction doesn't make it true. If it is true then there is credible evidence of that truth by statute or circumstance. It is not the responsibility of our government to keep us from going into error it is the responsibility of all of us to keep our government from going into error.