Yea while $ viability is true, it's better to think of as

1) using some potentially useful products as fuel to burning off things you don't want and

2) the buffer to keep non-steady inflows in a suitable ready condition for steady-state processing. (When real world steady-state is less than ideal.)

Number 2 is really what dominates the equation, as shutting in gas sources or even just turning off pipelines is incredibly more complicated than just an 'off' switch.

And turning back on is even more complicated. In the case of wells, once you shut in, turning back on may never result in the same level of production as before.