you use intuition to come up with the argument. then you use a proof to convince others.
https://terrytao.wordpress.com/career-advice/there%E2%80%99s...
> The point of rigour is not to destroy all intuition; instead, it should be used to destroy bad intuition while clarifying and elevating good intuition.
In mathematics, intuition is the starting point and guiding principle, but never worth anything by itself without rigour.