Knowledge can be organized based on its form.

One can focus on different aspects. It can causal connnections or objects and relations between them. This gives rise to a set of different approaches to organizing knowledge and explains the variety of systems thinking methods.

Causal Loop Diagrams for example focus on causal connections between different factors (or variables).

Institutional Analysis focuses on rules in the system.

There is a need for many different ways of analysing systems. Knowledge can take many forms and these different forms can be useful in different situations. It doesn't make too much sense to argue which approach is better. But it makes sense to know in what situations the given approach works best and when it should not be applied.

Article about learning in complex systems by John Sterman from MIT shows very well why we need systems thinking

How to intervene in complex systems in a way that small efforts bring a substantial change?

Jak interweniować w złożone systemy tak, żeby uzyskać dużą zmianę małym kosztem?

Read an article "Leverage Points Donella Meadows

A great book introducing the area of systems thinking:

Donella Meadows, Thinking in Systems