The difference is between broad consensus and divided opinion. A Constitutional amendment requires a 2/3 vote of Congress to propose, and ratification by 3/4 of states (which means any Constitutional amendment would require support from both red and blue states). Ordinary legislation only requires a 50% + 1 majority.
That's not really true of any non-budgetary legislation (for now).
Where that's approximately true, it's actually 50% + ½.
In the Senate, though, in practice, due to cloture, it potentially takes a 3/5 supermajority for most regular legislation.
Yea,that's like... The entire point of the constitution. This is like saying "what's the difference between changing a law or breaking and entering after asking your friend Jeb if it's ok".
I fully agree that the amendment process has to be used. I would be in favor of a 28th amendment placing well thought out limitations on the 1st or the 2nd amendments. Assuming I thought that the limitations it was placing on them were good limitations.