Halliday & Matthiessen (2014: 591):
We can thus identify a scale of strategies for construing the causal relation:(i) clause nexus, paratactic – middle clause: the fuse was overloaded, so it blew
(ii) clause nexus, hypotactic – middle clause: because the fuse was overloaded, it blew
(iii) verbal group nexus – effective clause: overloading caused the fuse to blow
(iv) verbal group – effective clause: overloading blew the fuse
…The point of these examples is to show how the grammar gives us considerable flexibility in construing the flow of events by providing a range of strategies. These strategies are all ideational, but they range from purely logical [(i) and (ii) above] via logical and experiential [(iii)] to purely experiential [(iv)].